Systems and methods for signaling subpicture information in video coding

ABSTRACT

A method of decoding video data is disclosed. The method comprising: parsing a first syntax element indicating a number of subpictures in a picture; for each of subpictures which are other than a first subpicture, parsing second syntax elements indicating a position of the each of subpictures; inferring a top-left position of the first subpicture equal to a top-left position of the picture.

TECHNICAL FIELD

This disclosure relates to video coding and more particularly to techniques for signaling picture information for coded video.

BACKGROUND ART

Digital video capabilities can be incorporated into a wide range of devices, including digital televisions, laptop or desktop computers, tablet computers, digital recording devices, digital media players, video gaming devices, cellular telephones, including so-called smartphones, medical imaging devices, and the like. Digital video may be coded according to a video coding standard. Video coding standards define the format of a compliant bitstream encapsulating coded video data. A compliant bitstream is a data structure that may be received and decoded by a video decoding device to generate reconstructed video data. Video coding standards may incorporate video compression techniques. Examples of video coding standards include ISO/IEC MPEG-4 Visual and ITU-T H.264 (also known as ISO/IEC MPEG-4 AVC) and High-Efficiency Video Coding (HEVC). HEVC is described in High Efficiency Video Coding (HEVC), Rec. ITU-T H.265, December 2016, which is incorporated by reference, and referred to herein as ITU-T H.265. Extensions and improvements for ITU-T H.265 are currently being considered for the development of next generation video coding standards. For example, the ITU-T Video Coding Experts Group (VCEG) and ISO/IEC (Moving Picture Experts Group (MPEG) (collectively referred to as the Joint Video Exploration Team (JVET)) are working to standardized video coding technology with a compression capability that significantly exceeds that of the current HEVC standard. The Joint Exploration Model 7 (JEM 7), Algorithm Description of Joint Exploration Test Model 7 (JEM 7), ISO/IEC JTC1/SC29/WG11 Document: JVET-G1001, July 2017, Torino, IT, which is incorporated by reference herein, describes the coding features that were under coordinated test model study by the JVET as potentially enhancing video coding technology beyond the capabilities of ITU-T H.265. It should be noted that the coding features of JEM 7 are implemented in JEM reference software. As used herein, the term JEM may collectively refer to algorithms included in JEM 7 and implementations of JEM reference software. Further, in response to a “Joint Call for Proposals on Video Compression with Capabilities beyond HEVC,” jointly issued by VCEG and MPEG, multiple descriptions of video coding tools were proposed by various groups at the 10^(th) Meeting of ISO/IEC JTC1/SC29/WG11 16-20 Apr. 2018, San Diego, Calif. From the multiple descriptions of video coding tools, a resulting initial draft text of a video coding specification is described in “Versatile Video Coding (Draft 1),” 10^(th) Meeting of ISO/IEC JTC1/SC29/WG11 16-20 Apr. 2018, San Diego, Calif., document JVET-J1001-v2, which is incorporated by reference herein, and referred to as JVET-J1001. The current development of a next generation video coding standard by the VCEG and MPEG is referred to as the Versatile Video Coding (VVC) project. “Versatile Video Coding (Draft 7),” 16th Meeting of ISO/IEC JTC1/SC29/WG11 1-11 Oct. 2019, Geneva, C H, document JVET-P2001-vE, which is incorporated by reference herein, and referred to as JVET-P2001, represents the current iteration of the draft text of a video coding specification corresponding to the VVC project.

Video compression techniques enable data requirements for storing and transmitting video data to be reduced. Video compression techniques may reduce data requirements by exploiting the inherent redundancies in a video sequence. Video compression techniques may sub-divide a video sequence into successively smaller portions (i.e., groups of pictures within a video sequence, a picture within a group of pictures, regions within a picture, sub-regions within regions, etc.). Intra prediction coding techniques (e.g., spatial prediction techniques within a picture) and inter prediction techniques (i.e., inter-picture techniques (temporal)) may be used to generate difference values between a unit of video data to be coded and a reference unit of video data. The difference values may be referred to as residual data. Residual data may be coded as quantized transform coefficients. Syntax elements may relate residual data and a reference coding unit (e.g., intra-prediction mode indices, and motion information). Residual data and syntax elements may be entropy coded. Entropy encoded residual data and syntax elements may be included in data structures forming a compliant bitstream.

SUMMARY OF INVENTION

In one example, a method of decoding video data, the method comprising: parsing a first syntax element indicating a number of subpictures in a picture; for each of subpictures which are other than a first subpicture, parsing second syntax elements indicating a position of the each of subpictures; inferring a top-left position of the first subpicture equal to a top-left position of the picture.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating an example of a system that may be configured to encode and decode video data according to one or more techniques of this disclosure.

FIG. 2 is a conceptual diagram illustrating coded video data and corresponding data structures according to one or more techniques of this disclosure.

FIG. 3 is a conceptual diagram illustrating a data structure encapsulating coded video data and corresponding metadata according to one or more techniques of this disclosure.

FIG. 4 is a conceptual drawing illustrating an example of components that may be included in an implementation of a system that may be configured to encode and decode video data according to one or more techniques of this disclosure.

FIG. 5 is a block diagram illustrating an example of a video encoder that may be configured to encode video data according to one or more techniques of this disclosure.

FIG. 6 is a block diagram illustrating an example of a video decoder that may be configured to decode video data according to one or more techniques of this disclosure.

DESCRIPTION OF EMBODIMENTS

In general, this disclosure describes various techniques for coding video data. In particular, this disclosure describes techniques for signaling picture information for coded video data. That is, for example, picture information may include information indicating whether one or more video coding tools (e.g., prediction techniques, filtering techniques, etc.) are enabled for a picture and/or portions thereof. It should be noted that although techniques of this disclosure are described with respect to ITU-T H.264, ITU-T H.265, JEM, and JVET-P2001, the techniques of this disclosure are generally applicable to video coding. For example, the coding techniques described herein may be incorporated into video coding systems, (including video coding systems based on future video coding standards) including video block structures, intra prediction techniques, inter prediction techniques, transform techniques, filtering techniques, and/or entropy coding techniques other than those included in ITU-T H.265, JEM, and JVET-P2001. Thus, reference to ITU-T H.264, ITU-T H.265, JEM, and/or JVET-P2001 is for descriptive purposes and should not be construed to limit the scope of the techniques described herein. Further, it should be noted that incorporation by reference of documents herein is for descriptive purposes and should not be construed to limit or create ambiguity with respect to terms used herein. For example, in the case where an incorporated reference provides a different definition of a term than another incorporated reference and/or as the term is used herein, the term should be interpreted in a manner that broadly includes each respective definition and/or in a manner that includes each of the particular definitions in the alternative.

In one example, a method of signaling picture information comprises signaling a syntax element indicating a number of subpictures in a picture and for each of the subpictures, other than the first subpicture, signaling syntax elements indicating the position of the subpicture.

In one example, a device comprises one or more processors configured to signal a syntax element indicating a number of subpictures in a picture and for each of the subpictures, other than the first subpicture, signal syntax elements indicating the position of the subpicture.

In one example, a non-transitory computer-readable storage medium comprises instructions stored thereon that, when executed, cause one or more processors of a device to signal a syntax element indicating a number of subpictures in a picture and for each of the subpictures, other than the first subpicture, signal syntax elements indicating the position of the subpicture.

In one example, an apparatus comprises means for signaling a syntax element indicating a number of subpictures in a picture and means for signaling syntax elements indicating the position of the subpicture for each of the subpictures, other than the first subpicture.

In one example, a method of decoding picture information for decoding video data comprises parsing a syntax element indicating a number of subpictures in a picture and for each of the subpictures, other than the first subpicture, parsing syntax elements indicating the position of the subpicture.

In one example, a device comprises one or more processors configured to parse a syntax element indicating a number of subpictures in a picture and for each of the subpictures, other than the first subpicture, parse syntax elements indicating the position of the subpicture.

In one example, a non-transitory computer-readable storage medium comprises instructions stored thereon that, when executed, cause one or more processors of a device to parse a syntax element indicating a number of subpictures in a picture and for each of the subpictures, other than the first subpicture, parse syntax elements indicating the position of the subpicture.

In one example, an apparatus comprises means for parsing a syntax element indicating a number of subpictures in a picture and means for parsing syntax elements indicating the position of the subpicture for each of the subpictures, other than the first subpicture.

The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

Video content includes video sequences comprised of a series of frames (or pictures). A series of frames may also be referred to as a group of pictures (GOP). Each video frame or picture may divided into one or more regions. Regions may be defined according to a base unit (e.g., a video block) and sets of rules defining a region. For example, a rule defining a region may be that a region must be an integer number of video blocks arranged in a rectangle. Further, video blocks in a region may be ordered according to a scan pattern (e.g., a raster scan). As used herein, the term video block may generally refer to an area of a picture or may more specifically refer to the largest array of sample values that may be predictively coded, sub-divisions thereof, and/or corresponding structures. Further, the term current video block may refer to an area of a picture being encoded or decoded. A video block may be defined as an array of sample values. It should be noted that in some cases pixel values may be described as including sample values for respective components of video data, which may also be referred to as color components, (e.g., luma (Y) and chroma (Cb and Cr) components or red, green, and blue components). It should be noted that in some cases, the terms pixel value and sample value are used interchangeably. Further, in some cases, a pixel or sample may be referred to as a pel. A video sampling format, which may also be referred to as a chroma format, may define the number of chroma samples included in a video block with respect to the number of luma samples included in a video block. For example, for the 4:2:0 sampling format, the sampling rate for the luma component is twice that of the chroma components for both the horizontal and vertical directions.

A video encoder may perform predictive encoding on video blocks and sub-divisions thereof. Video blocks and sub-divisions thereof may be referred to as nodes. ITU-T H.264 specifies a macroblock including 16×16 luma samples. That is, in ITU-T H.264, a picture is segmented into macroblocks. ITU-T H.265 specifies an analogous Coding Tree Unit (CTU) structure (which may be referred to as a largest coding unit (LCU)). In ITU-T H.265, pictures are segmented into CTUs. In ITU-T H.265, for a picture, a CTU size may be set as including 16×16, 32×32, or 64×64 luma samples. In ITU-T H.265, a CTU is composed of respective Coding Tree Blocks (CTB) for each component of video data (e.g., luma (Y) and chroma (Cb and Cr). It should be noted that video having one luma component and the two corresponding chroma components may be described as having two channels, i.e., a luma channel and a chroma channel. Further, in ITU-T H.265, a CTU may be partitioned according to a quadtree (QT) partitioning structure, which results in the CTBs of the CTU being partitioned into Coding Blocks (CB). That is, in ITU-T H.265, a CTU may be partitioned into quadtree leaf nodes. According to ITU-T H.265, one luma CB together with two corresponding chroma CBs and associated syntax elements are referred to as a coding unit (CU). In ITU-T H.265, a minimum allowed size of a CB may be signaled. In ITU-T H.265, the smallest minimum allowed size of a luma CB is 8×8 luma samples. In ITU-T H.265, the decision to code a picture area using intra prediction or inter prediction is made at the CU level.

In ITU-T H.265, a CU is associated with a prediction unit structure having its root at the CU. In ITU-T H.265, prediction unit structures allow luma and chroma CBs to be split for purposes of generating corresponding reference samples. That is, in ITU-T H.265, luma and chroma CBs may be split into respective luma and chroma prediction blocks (PBs), where a PB includes a block of sample values for which the same prediction is applied. In ITU-T H.265, a CB may be partitioned into 1, 2, or 4 PBs. ITU-T H.265 supports PB sizes from 64×64 samples down to 4×4 samples. In ITU-T H.265, square PBs are supported for intra prediction, where a CB may form the PB or the CB may be split into four square PBs. In ITU-T H.265, in addition to the square PBs, rectangular PBs are supported for inter prediction, where a CB may by halved vertically or horizontally to form PBs. Further, it should be noted that in ITU-T H.265, for inter prediction, four asymmetric PB partitions are supported, where the CB is partitioned into two PBs at one quarter of the height (at the top or the bottom) or width (at the left or the right) of the CB. Intra prediction data (e.g., intra prediction mode syntax elements) or inter prediction data (e.g., motion data syntax elements) corresponding to a PB is used to produce reference and/or predicted sample values for the PB.

JEM specifies a CTU having a maximum size of 256×256 luma samples. JEM specifies a quadtree plus binary tree (QTBT) block structure. In JEM, the QTBT structure enables quadtree leaf nodes to be further partitioned by a binary tree (BT) structure. That is, in JEM, the binary tree structure enables quadtree leaf nodes to be recursively divided vertically or horizontally. In JVET-P2001, CTUs are partitioned according a quadtree plus multi-type tree (QTMT or QT+MTT) structure. The QTMT in JVET-P2001 is similar to the QTBT in JEM. However, in JVET-P2001, in addition to indicating binary splits, the multi-type tree may indicate so-called ternary (or triple tree (TT)) splits. A ternary split divides a block vertically or horizontally into three blocks. In the case of a vertical TT split, a block is divided at one quarter of its width from the left edge and at one quarter its width from the right edge and in the case of a horizontal TT split a block is at one quarter of its height from the top edge and at one quarter of its height from the bottom edge.

As described above, each video frame or picture may be divided into one or more regions. For example, according to ITU-T H.265, each video frame or picture may be partitioned to include one or more slices and further partitioned to include one or more tiles, where each slice includes a sequence of CTUs (e.g., in raster scan order) and where a tile is a sequence of CTUs corresponding to a rectangular area of a picture. It should be noted that a slice, in ITU-T H.265, is a sequence of one or more slice segments starting with an independent slice segment and containing all subsequent dependent slice segments (if any) that precede the next independent slice segment (if any). A slice segment, like a slice, is a sequence of CTUs. Thus, in some cases, the terms slice and slice segment may be used interchangeably to indicate a sequence of CTUs arranged in a raster scan order. Further, it should be noted that in ITU-T H.265, a tile may consist of CTUs contained in more than one slice and a slice may consist of CTUs contained in more than one tile. However, ITU-T H.265 provides that one or both of the following conditions shall be fulfilled: (1) All CTUs in a slice belong to the same tile; and (2) All CTUs in a tile belong to the same slice.

With respect to JVET-P2001, slices are required to consist of an integer number of complete tiles or an integer number of consecutive complete CTU rows within a tile, instead of only being required to consist of an integer number of CTUs. It should be noted that in JVET-P2001, the slice design does not include slice segments (i.e., no independent/dependent slice segments). Thus, in JVET-P2001, a picture may include a single tile, where the single tile is contained within a single slice or a picture may include multiple tiles where the multiple tiles (or CTU rows thereof) may be contained within one or more slices. In JVET-P2001, the partitioning of a picture into tiles is specified by specifying respective heights for tile rows and respective widths for tile columns. Thus, in JVET-P2001 a tile is a rectangular region of CTUs within a particular tile row and a particular tile column position. Further, it should be noted that JVET-P2001 provides where a picture may be partitioned into subpictures, where a subpicture is a rectangular region of a CTUs within a picture. The top-left CTU of a subpicture may be located at any CTU position within a picture with subpictures being constrained to include one or more slices Thus, unlike a tile, a subpicture is not necessarily limited to a particular row and column position. It should be noted that subpictures may be useful for encapsulating regions of interest within a picture and a sub-bitstream extraction process may be used to only decode and display a particular region of interest. That is, as described in further detail below, a bitstream of coded video data includes a sequence of network abstraction layer (NAL) units, where a NAL unit encapsulates coded video data, (i.e., video data corresponding to a slice of picture) or a NAL unit encapsulates metadata used for decoding video data (e.g., a parameter set) and a sub-bitstream extraction process forms a new bitstream by removing one or more NAL units from a bitstream.

FIG. 2 is a conceptual diagram illustrating an example of a picture within a group of pictures partitioned according to tiles, slices, and subpictures. It should be noted that the techniques described herein may be applicable to tiles, slices, subpictures, sub-divisions thereof and/or equivalent structures thereto. That is, the techniques described herein may be generally applicable regardless of how a picture is partitioned into regions. For example, in some cases, the techniques described herein may be applicable in cases where a tile may be partitioned into so-called bricks, where a brick is a rectangular region of CTU rows within a particular tile. Further, for example, in some cases, the techniques described herein may be applicable in cases where one or more tiles may be included in so-called tile groups, where a tile group includes an integer number of adjacent tiles. In one example, a tile group may be called a slice. In the example illustrated in FIG. 2 , Pic₃ is illustrated as including 16 tiles (i.e., Tile₀ to Tile₁₅) and three slices (i.e., Slice₀ to Slice₂). In the example illustrated in FIG. 2 , Slice₀ includes four tiles (i.e., Tile₀ to Tile₃), Slice₁ includes eight tiles (i.e., Tile₄ to Tile₁₁), and Slice₂ includes four tiles (i.e., Tile₁₂ to Tile₁₅). Further, as illustrated in the example of FIG. 2 , Pic₃ is illustrated as including two subpictures (i.e., Subpicture₀ and Subpicture₁), where Subpicture₀ includes Slice₀ and Slice₁ and where Subpicture₁ includes Slice₂. As described above, subpictures may be useful for encapsulating regions of interest within a picture and a sub-bitstream extraction process may be used in order to selectively decode (and display) a region interest. For example, referring to FIG. 2 , Subpicture₀ may corresponding to an action portion of a sporting event presentation (e.g., a view of the field) and Subpicture₁ may corresponding to a scrolling banner displayed during the sporting event presentation. By using organizing a picture into subpictures in this manner, a viewer may be able to disable the display of the scrolling banner. That is, through a sub-bitstream extraction process Slice₂ NAL unit may be removed from a bitstream (and thus not decoded) and Slice₀ NAL unit and Slice₁ NAL unit may be decoded and displayed. The encapsulation of slices of a picture into respective NAL unit data structures and sub-bitstream extraction are described in further detail below.

For intra prediction coding, an intra prediction mode may specify the location of reference samples within a picture. In ITU-T H.265, defined possible intra prediction modes include a planar (i.e., surface fitting) prediction mode, a DC (i.e., flat overall averaging) prediction mode, and 33 angular prediction modes (predMode: 2-34). In JEM, defined possible intra-prediction modes include a planar prediction mode, a DC prediction mode, and 65 angular prediction modes. It should be noted that planar and DC prediction modes may be referred to as non-directional prediction modes and that angular prediction modes may be referred to as directional prediction modes. It should be noted that the techniques described herein may be generally applicable regardless of the number of defined possible prediction modes.

For inter prediction coding, a reference picture is determined and a motion vector (MV) identifies samples in the reference picture that are used to generate a prediction for a current video block. For example, a current video block may be predicted using reference sample values located in one or more previously coded picture(s) and a motion vector is used to indicate the location of the reference block relative to the current video block. A motion vector may describe, for example, a horizontal displacement component of the motion vector (i.e., MV_(x)), a vertical displacement component of the motion vector (i.e., MV_(y)), and a resolution for the motion vector (e.g., one-quarter pixel precision, one-half pixel precision, one-pixel precision, two-pixel precision, four-pixel precision). Previously decoded pictures, which may include pictures output before or after a current picture, may be organized into one or more to reference pictures lists and identified using a reference picture index value. Further, in inter prediction coding, uni-prediction refers to generating a prediction using sample values from a single reference picture and bi-prediction refers to generating a prediction using respective sample values from two reference pictures. That is, in uni-prediction, a single reference picture and corresponding motion vector are used to generate a prediction for a current video block and in bi-prediction, a first reference picture and corresponding first motion vector and a second reference picture and corresponding second motion vector are used to generate a prediction for a current video block. In bi-prediction, respective sample values are combined (e.g., added, rounded, and clipped, or averaged according to weights) to generate a prediction. Pictures and regions thereof may be classified based on which types of prediction modes may be utilized for encoding video blocks thereof. That is, for regions having a B type (e.g., a B slice), bi-prediction, uni-prediction, and intra prediction modes may be utilized, for regions having a P type (e.g., a P slice), uni-prediction, and intra prediction modes may be utilized, and for regions having an I type (e.g., an I slice), only intra prediction modes may be utilized. As described above, reference pictures are identified through reference indices. For example, for a P slice, there may be a single reference picture list, RefPicList0 and for a B slice, there may be a second independent reference picture list, RefPicList1, in addition to RefPicList0. It should be noted that for uni-prediction in a B slice, one of RefPicList0 or RefPicList1 may be used to generate a prediction. Further, it should be noted that during the decoding process, at the onset of decoding a picture, reference picture list(s) are generated from previously decoded pictures stored in a decoded picture buffer (DPB).

Further, a coding standard may support various modes of motion vector prediction. Motion vector prediction enables the value of a motion vector for a current video block to be derived based on another motion vector. For example, a set of candidate blocks having associated motion information may be derived from spatial neighboring blocks and temporal neighboring blocks to the current video block. Further, generated (or default) motion information may be used for motion vector prediction. Examples of motion vector prediction include advanced motion vector prediction (AMVP), temporal motion vector prediction (TMVP), so-called “merge” mode, and “skip” and “direct” motion inference. Further, other examples of motion vector prediction include advanced temporal motion vector prediction (ATMVP) and Spatial-temporal motion vector prediction (STMVP). For motion vector prediction, both a video encoder and video decoder perform the same process to derive a set of candidates. Thus, for a current video block, the same set of candidates is generated during encoding and decoding.

As described above, for inter prediction coding, reference samples in a previously coded picture are used for coding video blocks in a current picture. Previously coded pictures which are available for use as reference when coding a current picture are referred as reference pictures. It should be noted that the decoding order does not necessary correspond with the picture output order, i.e., the temporal order of pictures in a video sequence. In ITU-T H.265, when a picture is decoded it is stored to a decoded picture buffer (DPB) (which may be referred to as frame buffer, a reference buffer, a reference picture buffer, or the like). In ITU-T H.265, pictures stored to the DPB are removed from the DPB when they been output and are no longer needed for coding subsequent pictures. In ITU-T H.265, a determination of whether pictures should be removed from the DPB is invoked once per picture, after decoding a slice header, i.e., at the onset of decoding a picture. For example, referring to FIG. 2 , Pic₂ is illustrated as referencing Pic₁. Similarly, Pic₃ is illustrated as referencing Pic₀. With respect to FIG. 2 , assuming the picture number corresponds to the decoding order, the DPB would be populated as follows: after decoding Pic₀, the DPB would include {Pic₀}; at the onset of decoding Pic₁, the DPB would include {Pic₀}; after decoding Pic₁, the DPB would include {Pic₀, Pic₁}; at the onset of decoding Pic₂, the DPB would include {Pic₀, Pic₁}. Pic₂ would then be decoded with reference to Pic₁ and after decoding Pic₂, the DPB would include {Pic₀, Pic₁, Pic₂}. At the onset of decoding Pic₃, pictures Pic₀ and Pic₁ would be marked for removal from the DPB, as they are not needed for decoding Pic₃ (or any subsequent pictures, not shown) and assuming Pic₁ and Pic₂ have been output, the DPB would be updated to include {Pic₀}. Pic₃ would then be decoded by referencing Pic₀. The process of marking pictures for removal from a DPB may be referred to as reference picture set (RPS) management.

As described above, intra prediction data or inter prediction data is used to produce reference sample values for a block of sample values. The difference between sample values included in a current PB, or another type of picture area structure, and associated reference samples (e.g., those generated using a prediction) may be referred to as residual data. Residual data may include respective arrays of difference values corresponding to each component of video data. Residual data may be in the pixel domain. A transform, such as, a discrete cosine transform (DCT), a discrete sine transform (DST), an integer transform, a wavelet transform, or a conceptually similar transform, may be applied to an array of difference values to generate transform coefficients. It should be noted that in ITU-T H.265 and JVET-P2001, a CU is associated with a transform tree structure having its root at the CU level. The transform tree is partitioned into one or more transform units (TUs). That is, an array of difference values may be partitioned for purposes of generating transform coefficients (e.g., four 8×8 transforms may be applied to a 16×16 array of residual values). For each component of video data, such sub-divisions of difference values may be referred to as Transform Blocks (TBs). It should be noted that in some cases, a core transform and a subsequent secondary transforms may be applied (in the video encoder) to generate transform coefficients. For a video decoder, the order of transforms is reversed.

A quantization process may be performed on transform coefficients or residual sample values directly (e.g., in the case, of palette coding quantization). Quantization approximates transform coefficients by amplitudes restricted to a set of specified values. Quantization essentially scales transform coefficients in order to vary the amount of data required to represent a group of transform coefficients. Quantization may include division of transform coefficients (or values resulting from the addition of an offset value to transform coefficients) by a quantization scaling factor and any associated rounding functions (e.g., rounding to the nearest integer). Quantized transform coefficients may be referred to as coefficient level values. Inverse quantization (or “dequantization”) may include multiplication of coefficient level values by the quantization scaling factor, and any reciprocal rounding or offset addition operations. It should be noted that as used herein the term quantization process in some instances may refer to division by a scaling factor to generate level values and multiplication by a scaling factor to recover transform coefficients in some instances. That is, a quantization process may refer to quantization in some cases and inverse quantization in some cases. Further, it should be noted that although in some of the examples below quantization processes are described with respect to arithmetic operations associated with decimal notation, such descriptions are for illustrative purposes and should not be construed as limiting. For example, the techniques described herein may be implemented in a device using binary operations and the like. For example, multiplication and division operations described herein may be implemented using bit shifting operations and the like.

Quantized transform coefficients and syntax elements (e.g., syntax elements indicating a coding structure for a video block) may be entropy coded according to an entropy coding technique. An entropy coding process includes coding values of syntax elements using lossless data compression algorithms. Examples of entropy coding techniques include content adaptive variable length coding (CAVLC), context adaptive binary arithmetic coding (CABAC), probability interval partitioning entropy coding (PIPE), and the like. Entropy encoded quantized transform coefficients and corresponding entropy encoded syntax elements may form a compliant bitstream that can be used to reproduce video data at a video decoder. An entropy coding process, for example, CABAC, may include performing a binarization on syntax elements. Binarization refers to the process of converting a value of a syntax element into a series of one or more bits. These bits may be referred to as “bins.” Binarization may include one or a combination of the following coding techniques: fixed length coding, unary coding, truncated unary coding, truncated Rice coding, Golomb coding, k-th order exponential Golomb coding, and Golomb-Rice coding. For example, binarization may include representing the integer value of 5 for a syntax element as 00000101 using an 8-bit fixed length binarization technique or representing the integer value of 5 as 11110 using a unary coding binarization technique. As used herein each of the terms fixed length coding, unary coding, truncated unary coding, truncated Rice coding, Golomb coding, k-th order exponential Golomb coding, and Golomb-Rice coding may refer to general implementations of these techniques and/or more specific implementations of these coding techniques. For example, a Golomb-Rice coding implementation may be specifically defined according to a video coding standard. In the example of CABAC, for a particular bin, a context provides a most probable state (MPS) value for the bin (i.e., an MPS for a bin is one of 0 or 1) and a probability value of the bin being the MPS or the least probably state (LPS). For example, a context may indicate, that the MPS of a bin is 0 and the probability of the bin being 1 is 0.3. It should be noted that a context may be determined based on values of previously coded bins including bins in the current syntax element and previously coded syntax elements. For example, values of syntax elements associated with neighboring video blocks may be used to determine a context for a current bin.

-   -   With respect to the equations used herein, the following         arithmetic operators may be used:         -   + Addition         -   − Subtraction         -   * Multiplication, including matrix multiplication         -   x^(y) Exponentiation. Specifies x to the power of y. In             other contexts, such notation is used for superscripting not             intended for interpretation as exponentiation.         -   / Integer division with truncation of the result toward             zero. For example, 7/4 and −7/−4 are truncated to 1 and −7/4             and 7/−4 are truncated to −1.         -   ÷ Used to denote division in mathematical equations where no             truncation or rounding is intended.

$\frac{x}{y}$

-   -   -    Used to denote division in mathematical equations where no             truncation or rounding is intended.

    -   Further, the following mathematical functions may be used:         -   Log2(x) the base-2 logarithm of x;

${{Min}\left( {x,y} \right)} = \left\{ {\begin{matrix} {x;} & {x<=y} \\ {y;} & {x > y} \end{matrix};{{{Max}\left( {x,y} \right)} = \left\{ \begin{matrix} {x;} & {x>=y} \\ {y;} & {x < y} \end{matrix} \right.}} \right.$

-   -   -   Ceil(x) the smallest integer greater than or equal to x.

    -   With respect to the example syntax used herein, the following         definitions of logical operators may be applied:         -   x && y Boolean logical “and” of x and y         -   x∥y Boolean logical “or” of x and y         -   ! Boolean logical “not”         -   x? y: z If x is TRUE or not equal to 0, evaluates to the             value of y; otherwise, evaluates to the value of z.

    -   Further, the following relational operators may be applied:         -   > Greater than         -   >= Greater than or equal to         -   < Less than         -   <= Less than or equal to         -   == Equal to         -   != Not equal to

    -   Further, it should be noted that in the syntax descriptors used         herein, the following descriptors may be applied:         -   b(8): byte having any pattern of bit string (8 bits). The             parsing process for this descriptor is specified by the             return value of the function read_bits(8).         -   f(n): fixed-pattern bit string using n bits written (from             left to right) with the left bit first. The parsing process             for this descriptor is specified by the return value of the             function read_bits(n).         -   se(v): signed integer 0-th order Exp-Golomb-coded syntax             element with the left bit first.         -   tb(v): truncated binary using up to maxVal bits with maxVal             defined in the semantics of the syntax element.         -   tu(v): truncated unary using up to maxVal bits with maxVal             defined in the semantics of the syntax element.         -   u(n): unsigned integer using n bits. When n is “v” in the             syntax table, the number of bits varies in a manner             dependent on the value of other syntax elements. The parsing             process for this descriptor is specified by the return value             of the function read_bits(n) interpreted as a binary             representation of an unsigned integer with most significant             bit written first.         -   ue(v): unsigned integer 0-th order Exp-Golomb-coded syntax             element with the left bit first.

As described above, video content includes video sequences comprised of a series of pictures and each picture may be divided into one or more regions. In JVET-P2001, a coded representation of a picture is referred to as a coded picture and all CTUs of the coded picture are encapsulated in one or more coded slice NAL units. That is, one or more corresponding coded slice NAL units encapsulate a coded representation of a picture. For example, referring again to FIG. 2 , the coded representation of Pic₃ is encapsulated in three coded slice NAL units (i.e., Slice₀ NAL unit, Slice₁ NAL unit, and Slice₂ NAL unit). It should be noted that the term video coding layer (VCL) NAL unit is used as a collective term for coded slice NAL units, i.e., VCL NAL is a collective term which includes all types of slice NAL units. As described above, and in further detail below, a NAL unit may encapsulate metadata used for decoding video data. A NAL unit encapsulating metadata used for decoding a video sequence is generally referred to as a non-VCL NAL unit. Thus, in JVET-P2001, a NAL unit may be a VCL NAL unit or a non-VCL NAL unit. It should be noted that a VCL NAL unit includes slice header data, which provides information used for decoding the particular slice. Thus, in JVET-P2001, information used for decoding video data, which may be referred to as metadata in some cases, is not limited to being included in non-VCL NAL units. JVET-P2001 provides where a picture unit (PU) is a set of NAL units that contain all VCL NAL units of a coded picture and their associated non-VCL NAL units and where an access unit (AU) is a set of NAL units that are associated with each other according to a specified classification rule, are consecutive in decoding order, and contain exactly one coded picture for each present picture unit. A PU consists of one picture header NAL unit, one coded picture, which comprises of one or more VCL NAL units, and zero or more non-VCL NAL units. Thus, in JVET-P2001 an access unit includes one or more coded pictures. In some cases, an access unit may include pictures included in different layers of video. Layers of video are described in further detail below. Further, in JVET-P2001, a coded video sequence (CVS) is a sequence of AUs that consists, in decoding order, of a CVSS AU, followed by zero or more AUs that are not CVSS AUs, including all subsequent AUs up to but not including any subsequent AU that is a CVSS AU, where a coded video sequence start (CVSS) AU is an AU in which there is a picture unit for each layer in the CVS and the coded picture in each present picture unit is a coded layer video sequence start (CLVSS) picture. In JVET-P2001, a coded layer video sequence (CLVS) is a sequence of PUs within the same layer that consists, in decoding order, of a CLVSS PU, followed by zero or more PUs that are not CLVSS PUs, including all subsequent PUs up to but not including any subsequent PU that is a CLVSS PU. This is, in JVET-P2001, a bitstream may be described as including a sequence of NAL units forming a CVS, where a CVS includes AUs and each AU may include respective pictures for each of a plurality of layers for coded video.

Multi-layer video coding enables a video presentation to be decoded/displayed as a presentation corresponding to a base layer of video data and decoded/displayed one or more additional presentations corresponding to enhancement layers of video data. For example, a base layer may enable a video presentation having a basic level of quality (e.g., a High Definition rendering and/or a 30 Hz frame rate) to be presented and an enhancement layer may enable a video presentation having an enhanced level of quality (e.g., an Ultra High Definition rendering and/or a 60 Hz frame rate) to be presented. An enhancement layer may be coded by referencing a base layer. That is, for example, a picture in an enhancement layer may be coded (e.g., using inter-layer prediction techniques) by referencing one or more pictures (including scaled versions thereof) in a base layer. It should be noted that layers may also be coded independent of each other. In this case, there may not be inter-layer prediction between two layers. Each NAL unit may include an identifier indicating a layer of video data the NAL unit is associated with. As described above, a sub-bitstream extraction process may be used to only decode and display a particular region of interest of a picture. Further, a sub-bitstream extraction process may be used to only decode and display a particular layer of video. Sub-bitstream extraction may refer to a process where a device receiving a compliant or conforming bitstream forms a new compliant or conforming bitstream by discarding and/or modifying data in the received bitstream. For example, sub-bitstream extraction may be used to form a new compliant or conforming bitstream corresponding to a particular representation of video (e.g., a high quality representation).

In JVET-P2001, each of a video sequence, a GOP, a picture, a slice, and CTU may be associated with metadata that describes video coding properties and some types of metadata an encapsulated in non-VCL NAL units. JVET-P2001 defines parameters sets that may be used to describe video data and/or video coding properties. In particular, JVET-P2001 includes the following five types of parameter sets: decoding parameter set (DPS), video parameter set (VPS), sequence parameter set (SPS), picture parameter set (PPS), and adaption parameter set (APS), where a SPS applies to apply to zero or more entire CVSs, a PPS applies to zero or more entire coded pictures, a APS applies to zero or more slices, and a DPS and a VPS may be optionally referenced by a SPS. A PPS applies to an individual coded picture that refers to it. In JVET-P2001, parameter sets may be encapsulated as a non-VCL NAL unit and/or may be signaled as a message. JVET-P2001 also includes a picture header (PH) which is encapsulated as a non-VCL NAL unit. In JVET-P2001, a picture header applies to all slices of a coded picture. JVET-P2001 further enables supplemental enhancement information (SEI) messages to be signaled. In JVET-P2001, SEI messages assist in processes related to decoding, display or other purposes, however, SEI messages may not be required for constructing the luma or chroma samples according to a decoding process. In JVET-P2001, SEI messages may be signaled in a bitstream using non-VCL NAL units. Further, SEI messages may be conveyed by some mechanism other than by being present in the bitstream (i.e., signaled out-of-band).

FIG. 3 illustrates an example of a bitstream including multiple CVSs, where a CVS includes AUs, and AUs include picture units. The example illustrated in FIG. 3 corresponds to an example of encapsulating the slice NAL units illustrated in the example of FIG. 2 in a bitstream. In the example illustrated in FIG. 3 , the corresponding picture unit for Pic₃ includes the three VCL NAL coded slice NAL units, i.e., Slice₀ NAL unit, Slice₁ NAL unit, and Slice₂ NAL unit and two non-VCL NAL units, i.e., a PPS NAL Unit and a PH NAL unit. It should be noted that in FIG. 3 , HEADER is a NAL unit header (i.e., not to be confused with a slice header). Further, it should be noted that in FIG. 3 , other non-VCL NAL units, which are not illustrated may be included in the CVSs, e.g., SPS NAL units, VPS NAL units, SEI message NAL units, etc. Further, it should be noted that in other examples, a PPS NAL Unit used for decoding Pic₃ may be included elsewhere in the bitstream, e.g., in the picture unit corresponding to Pic₀ or may be provided by an external mechanism. However, it should be note that in JVET-P2001, the picture header for each picture is required to be in the picture unit corresponding to the picture.

-   -   JVET-P2001 defines NAL unit header semantics that specify the         type of Raw Byte Sequence Payload (RBSP) data structure included         in the NAL unit. Table 1 illustrates the syntax of the NAL unit         header provided in JVET-P2001.

TABLE 1 nal_unit_header( ) { Descriptor  forbidden_zero_bit f(1)  nuh_reserved_zero_bit u(1)  nuh_layer_id u(6)  nal_unit_type u(5)  nuh_temporal_id_plus1 u(3) }

-   -   JVET-P2001 provides the following definitions for the respective         syntax elements illustrated in Table 1.     -   forbidden_zero_bit shall be equal to 0.     -   nah_reserved_zero_bit shall be equal to ‘0’. The value 1 of         nuh_reserved_zero_bit may be specified in the future by         ITU-T|ISO/IEC. Decoders shall ignore (i.e. remove from the         bitstream and discard) NAL units with nuh_reserved_zero_bit         equal to ‘1’.     -   nuh_layer_id specifies the identifier of the layer to which a         VCL NAL unit belongs or the identifier of a layer to which a         non-VCL NAL unit applies. The value of nuh_layer_id shall be in         the range of 0 to 56, inclusive. Other values for nuh_layer_id         are reserved for future use by ITU-T|ISO/IEC.     -   The value of nuh_layer_id shall be the same for all VCL NAL         units of a coded picture. The value of nuh_layer_id of a coded         picture or a PU is the value of the nuh_layer_id of the VCL NAL         units of the coded picture or the PU.     -   The value of nuh_layer_id for non-VCL NAL units is constrained         as follows:         -   If nal_unit_type is equal to PPS_NUT, PREFIX_APS_NUT, or             SUFFIX_APS_NUT, nuh_layer_id shall be equal to the lowest             nuh_layer_id value of the coded slice NAL units that refer             to the NAL unit.         -   Otherwise if nal_unit_type is equal to SPS_NUT, nuh_layer_id             shall be equal to the lowest nuh_layer_id value of the PPS             NAL units that refer to the SPS NAL unit.         -   Otherwise when nal_unit_type is equal to PH_NUT, EOS_NUT, or             FD_NUT, nuh_layer_id shall be equal to the nuh_layer_id of             associated VCL NAL unit.     -   NOTE—The value of nuh_layer_id of DPS, VPS, EOB, and AUD NAL         units is not constrained.     -   The value of nal_unit_type shall be the same for all pictures of         a CVSS AU.     -   nul_temporal_id_plus1 minus 1 specifies a temporal identifier         for the NAL unit.     -   The value of nuh_temporal_id_plus1 shall not be equal to 0.     -   The variable TemporalId is derived as follows:

TemporalId=nuh_temporal_id_plus1−1

-   -   When nal_unit_type is in the range of IDR_W_RADL to RSV_IRAP_12,         inclusive, TemporalId shall be equal to 0.     -   When nal_unit_type is equal to STSA_NUT, TemporalId shall not be         equal to 0.     -   The value of TemporalId shall be the same for all VCL NAL units         of an AU. The value of TemporalId of a coded picture, a PU, or         an AU is the value of the TemporalId of the VCL NAL units of the         coded picture, PU, or AU. The value of TemporalId of a sub-layer         representation is the greatest value of TemporalId of all VCL         NAL units in the sub-layer representation.     -   The value of TemporalId for non-VCL NAL units is constrained as         follows:         -   If nal_unit_type is equal to DPS_NUT, VPS_NUT, or SPS_NUT,             TemporalId shall be equal to 0 and the TemporalId of the AU             containing the NAL unit shall be equal to 0.         -   Otherwise, if nal_unit_type is equal to PH_NUT, TemporalId             shall be equal to the TemporalId of the PU containing the             NAL unit.         -   Otherwise if nal_unit_type is equal to EOS_NUT or EOB_NUT,             TemporalId shall be equal to 0.         -   Otherwise, if nal_unit_type is equal to AUD_NUT, FD_NUT,             PREFIX_SEI_NUT, or SUFFIX_SEI_NUT, TemporalId shall be equal             to the TemporalId of the AU containing the NAL unit.         -   Otherwise, when nal_unit_type is equal to PPS_NUT,             PREFIX_APS_NUT, or SUFFIX_APS_NUT, TemporalId shall be             greater than or equal to the TemporalId of the PU containing             the NAL unit.     -   NOTE—When the NAL unit is a non-VCL NAL unit, the value of         TemporalId is equal to the minimum value of the TemporalId         values of all AUs to which the non-VCL NAL unit applies. When         nal_unit_type is equal to PPS_NUT, PREFIX_APS_NUT, or         SUFFIX_APS_NUT, TemporalId may be greater than or equal to the         TemporalId of the containing AU, as all PPSs and APSs may be         included in the beginning of the bitstream (e.g., when they are         transported out-of-band, and the receiver places them at the         beginning of the bitstream), wherein the first coded picture has         TemporalId equal to 0.     -   nal_unit_type specifies the NAL unit type, i.e., the type of         RBSP data structure contained in the NAL unit as specified in         Table 2.     -   NAL units that have nal_unit_type in the range of UNSPEC28 . . .         UNSPEC31, inclusive, for which semantics are not specified,         shall not affect the decoding process specified in this         Specification.     -   NOTE—NAL unit types in the range of UNSPEC28 . . . UNSPEC31 may         be used as determined by the application. No decoding process         for these values of nal_unit_type is specified in this         Specification. Since different applications might use these NAL         unit types for different purposes, particular care must be         exercised in the design of encoders that generate NAL units with         these nal_unit_type values, and in the design of decoders that         interpret the content of NAL units with these nal_unit_type         values. This Specification does not define any management for         these values. These nal_unit_type values might only be suitable         for use in contexts in which “collisions” of usage (i.e.,         different definitions of the meaning of the NAL unit content for         the same nal_unit_type value) are unimportant, or not possible,         or are managed—e.g., defined or managed in the controlling         application or transport specification, or by controlling the         environment in which bitstreams are distributed.     -   For purposes other than determining the amount of data in the         decoding units of the bitstream, decoders shall ignore (remove         from the bitstream and discard) the contents of all NAL units         that use reserved values of nal_unit_type.     -   NOTE—This requirement allows future definition of compatible         extensions to this Specification.

TABLE 2 nal_unit_ Name of Content of NAL unit and NAL unit type nal_unit_type RBSP syntax structure type class 0 TRAIL_NUT Coded slice of a trailing picture VCL slice_layer_rbsp( ) 1 STSA_NUT Coded slice of an STSA picture VCL slice_layer_rbsp( ) 2 RADL_NUT Coded slice of a RADL picture VCL slice_layer_rbsp( ) 3 RASL_NUT Coded slice of a RASL picture VCL slice_layer_rbsp( ) 4 . . . 6 RSV_VCL_4 . . . Reserved non-IRAP VCL VCL RSV_VCL_6 NAL unit types 7 IDR_W_RADL Coded slice of an IDR picture VCL 8 IDR_N_LP slice_layer_rbsp( ) 9 CRA_NUT Coded slice of a CRA picture VCL silce_layer_rbsp( ) 10 GDR_NUT Coded slice of a GDR picture VCL slice_layer_rbsp( ) 11 RSV_IRAP_11 Reserved IRAP VCL VCL NAL unit types 12 RSV_IRAP_12 13 DPS_NUT Decoding parameter set non-VCL decoding_parameter_ set_rbsp( ) 14 VPS_NUT Video parameter set non-VCL video_parameter_set_rbsp( ) 15 SPS_NUT Sequence parameter set non-VCL seq_parameter_set_rbsp( ) 16 PPS_NUT Picture parameter set non-VCL pic_parameter_set_rbsp( ) 17 PREFIX_APS_ NUT Adaptation parameter set non-VCL 18 SUFFIX_APS_ NUT adaptation_parameter_ set_rbsp( ) 19 PH_NUT Picture header non-VCL picture_header_rbsp( ) 20 AUD_NUT AU delimiter non-VCL access_unit_delimiter_rbsp( ) 21 EOS_NUT End of sequence non-VCL end_of_seq_rbsp( ) 22 EOB_NUT End of bitstream non-VCL end_of_bitstream_rbsp( ) 23 PREFIX_SEL_ Supplemental enhancement non-VCL NUT information 24 SUFFIX_SEL_ sei_rbsp( ) NUT 25 FD_NUT Filler data non-VCL filler_data_rbsp( ) 26 RSV_NVCL_26 Reserved non-VCL NAL non-VCL unit types 27 RSV_NVCL_27 28 . . 31 UNSPEC_28 . . . Unspecified non-VCL non-VCL UNSPEC_31 NAL unit types

-   -   NOTE—A clean random access (CRA) picture may have associated         RASL or RADL pictures present in the bitstream.     -   NOTE—An instantaneous decoding refresh (IDR) picture having         nal_unit_type equal to IDR_N_LP does not have associated leading         pictures present in the bitstream. An IDR picture having         nal_unit_type equal to IDR_W_RADL does not have associated RASL         pictures present in the bitstream, but may have associated RADL         pictures in the bitstream.     -   For VCL NAL units of any particular picture, the following         applies:         -   If mixed_nalu_types_in_pic_flag is equal to 0, the value of             nal_unit_type shall be the same for all coded slice NAL             units of a picture. A picture or a PU is referred to as             having the same NAL unit type as the coded slice NAL units             of the picture or PU.         -   Otherwise (mixed_nalu_types_in_pic_flag equal to 1), one or             more of the VCL NAL units shall all have a particular value             of nal_unit_type in the range of IDR_W_RADL to CRA_NUT,             inclusive, and the other VCL NAL units shall all have a             particular value of nal_unit_type in the range of TRAIL_NUT             to RSV_VCL_6, inclusive, or equal to GRA_NUT.     -   For a single-layer bitstream, the following constraints apply:         -   Each picture, other than the first picture in the bitstream             in decoding order, is considered to be associated with the             previous IRAP picture in decoding order.         -   When a picture is a leading picture of an IRAP picture, it             shall be a RADL or RASL picture.         -   When a picture is a trailing picture of an IRAP picture, it             shall not be a RADL or RASL picture.         -   No RASL pictures shall be present in the bitstream that are             associated with an IDR picture.         -   No RADL pictures shall be present in the bitstream that are             associated with an IDR picture having nal_unit_type equal to             IDR_N_LP.         -   NOTE—It is possible to perform random access at the position             of an IRAP PU by discarding all PUs before the IRAP PU (and             to correctly decode the IRAP picture and all the subsequent             non-RASL pictures in decoding order), provided each             parameter set is available (either in the bitstream or by             external means not specified in this Specification) when it             is referenced.         -   Any picture that precedes an TRAP picture in decoding order             shall precede the IRAP picture in output order and shall             precede any RADL picture associated with the IRAP picture in             output order.         -   Any RASL picture associated with a CRA picture shall precede             any RADL picture associated with the CRA picture in output             order.         -   Any RASL picture associated with a CRA picture shall follow,             in output order, any IRAP picture that precedes the CRA             picture in decoding order.         -   If field_seq_flag is equal to 0 and the current picture is a             leading picture associated with an IRAP picture, it shall             precede, in decoding order, all non-leading pictures that             are associated with the same IRAP picture. Otherwise, let             picA and picB be the first and the last leading pictures, in             decoding order, associated with an IRAP picture,             respectively, there shall be at most one non-leading picture             preceding picA in decoding order, and there shall be no             non-leading picture between picA and picB in decoding order.

It should be noted that generally, an Intra Random Access Point (IRAP) picture is a picture that does not refer to any pictures other than itself for prediction in its decoding process. In JVET-P2001, an IRAP picture may be a clean random access (CRA) picture or an instantaneous decoder refresh (IDR) picture. In JVET-P2001, the first picture in the bitstream in decoding order must be an IRAP or a gradual decoding refresh (GDR) picture. JVET-P2001 describes the concept of a leading picture, which is a picture that precedes the associated IRAP picture in output order. JVET-P2001 further describes the concept of a trailing picture which is a non-IRAP picture that follows the associated IRAP picture in output order. Trailing pictures associated with an IRAP picture also follow the IRAP picture in decoding order. For IDR pictures, there are no trailing pictures that require reference to a picture decoded prior to the IDR picture. JVET-P2001 provides where a CRA picture may have leading pictures that follow the CRA picture in decoding order and contain inter picture prediction references to pictures decoded prior to the CRA picture. Thus, when the CRA picture is used as a random access point these leading pictures may not be decodable and are identified as random access skipped leading (RASL) pictures. The other type of picture that can follow an IRAP picture in decoding order and precede it in output order is the random access decodable leading (RADL) picture, which cannot contain references to any pictures that precede the IRAP picture in decoding order. A GDR picture, is a picture for which each VCL NAL unit has nal_unit_type equal to GDR_NUT. If the current picture is a GDR picture that is associated with a picture header which signals a syntax element receovery_poc_cnt and there is a picture picA that follows the current GDR picture in decoding order in the CLVS and that has PicOrderCntVal equal to the PicOrderCntVal of the current GDR picture plus the value of recovery_poc_cnt, the picture picA is referred to as the recovery point picture.

As provided in Table 2, a NAL unit may include a sequence parameter set syntax structure. Table 3 illustrates the sequence parameter set syntax structure as provided in JVET-P2001.

Des- seq_parameter_set_rbsp( ) { criptor  sps_decoding_parameter_set_id u(4)  sps_video_parameter_set_id u(4)  sps_max_sub_layers_minus1 u(3)  sps_reserved_zero_4bits u(4)  sps_ptl_dpb_hrd_params_present_flag u(1)  if( sps_ptl_dpb_hrd_params_present_flag )   profile_tier_level( 1, sps_max_sub_layers_minus1 )  gdr_enabled_flag u(1)  sps_seq_parameter_set_id u(4)  chroma_format_idc u(2)  if( chroma_format_idc = = 3 )   separate_colour_plane_flag u(1)  ref_pic_resampling_enabled_flag u(1)  sps_seq_parameter_set_id ue(v)  chroma_format_idc ue(v)  if( chroma_format_idc = = 3 )   separate_colour_plane_flag u(1)  pic_width_max_in_luma_samples ue(v)  pic_height_max_in_luma_samples ue(v)  sps_log2_ctu_size_minus5 u(2)  subpics_present_flag u(1)   sps_num_subpics_minus1 u(8)   for( i = 0;i <= sps_num_subpics_minus 1; i++ ) {    subpic_ctu_top_left_x[ i ] u(v)    subpic_ctu_top_left_y[ i ] u(v)    subpic_width_minus1[ i ] u(v)    subpic_height_minus1[ i ] u(v)    subpic_treated_as_pic_flag[ i ] u(1)    loop_filter_across_subpic_enabled_flag[ i ] u(1)   }  }  sps_subpic_id_present_flag u(1)  if( sps_subpics_id_present_flag ) {   sps_subpic_id_signalling_present_flag u(1)   if( sps_subpics_id_signalling_present_flag ) {    sps_subpic_id_len_minus1 ue(v)    for( i = 0; i <= sps_num_subpics_minus1; i++ )     sps_subpic_id[ i ] u(v)   }  }  bit_depth_minus8 ue(v)  min_qp_prime_ts_minus4 ue(v)  sps_weighted_pred_flag u(1)  sps_weighted_bipred_flag u(1)  log2_max_pic_order_ent_lsb_minus4 u(4)  sps_poc_msb_flag u(1)  if( sps_poc_msb_flag )   poc_msb_len_minus1 ue(v)  if( sps_max_sub_layers_minus1 > 0 )   sps_sub_layer_dpb_params_flag u(1)  if( sps_ptl_dpb_hrd_params_present_flag )   dpb_parameters( 0, sps_max_sub_layers_minus1,   sps_sub_layer_dpb_params_flag )  long_term_ref_pics_flag u(1)  inter_layer_ref_pics_present_flag uf1)  sps_idr_rpl_present_flag u(1)  rpl1_same_as_rpl0_flag u(1)  for( i = 0; i < !rpl1_same_as_rpl0_flag ? 2 : 1; i++ ) {   num_ref_pic_lists_in_sps[ i ] ue(v)   for( j = 0; j < num_ref_pic_lists_in_sps[ i ]; j++ )    ref_pic_list_struct( i, j )  }  if( ChromaArrayType != 0 )   qtbtt_dual_tree_intra_flag u(1)  log2_min_luma_coding_block_size_minus2 ue(v)  partition_constraints_override_enabled_flag u(1)  sps_log2_diff_min_qt_min_cb_intra_slice_luma ue(v)  sps_log2_diff_min_qt_min_cb_inter_slice ue(v)  sps_max_mtt_hierarchy_depth_inter_slice ue(v)  sps_max_mtt_hierarchy_depth_intra_slice_luma ue(v)  if( sps_max_mtt_hierarchy_depth_intra_slice_luma != 0 ) {   sps_log2_diff_max_bt_min_qt_intra_slice_luma ue(v)   sps_log2_diff_max_tt_min_qt_intra_slice_luma ue(v)  }  if( sps_max_mtt_hierarchy depth_inter_slice != 0 ) {   sps_log2_diff_max_bt_min_qt_inter_slice ue(v)   sps_log2_diff_max_tt_min_qt_inter_slice ue(v)  }  if( qtbtt_dual_tree_intra_flag ) {   sps_log2_diff_min_qt_min_cb_intra_slice_chroma ue(v)   sps_max_mtt_hierarchy_depth_intra_slice_chroma ue(v)   if( sps_max_mtt_hierarchy_depth_intra_   slice_chroma != 0 ) {    sps_log2_diff_max_bt_min_qt_intra_slice_chroma ue(v)    sps_log2_diff_max_tt_min_qt_intra_slice_chroma ue(v)   }  }  sps_max_luma_transform_size_64_flag u(1)  sps_joint_cbcr_enabled_flag u(1)  if( ChromaArrayType != 0 ) {   same_qp_table_for_chroma u(1)   numQpTables = same_qp_table_for_chroma ? 1 :   ( sps_joint_cber_enabled_flag ? 3 : 2 )   for( i = 0; i < numQpTables; i++) {    qp_table_start_minus26[ i ] se(v)    num_points_in_qp_table_minus1[ i ] ue(v)    for( j = 0; j <= num_points_in_qptable_    minus1[ i ]; j++ ) {     delta_qp_in_val_minus1[ i ][ j ] ue(v)     delta_qp_diff_val[ i ][ j ] ue(v)    }   }  }  sps_sao_enabled_flag u(1)  sps_alf_enabled_flag u(1)  sps_transform_skip_enabled_flag u(1)  if( sps_transform_skip_enabled_flag )   sps_bdpcm_enabled_flag u(1)  if( sps_bdpcm_enabled_flag && chroma_format_idc = = 3 )   sps_bdpcm_chroma_enabled_flag u(1)  sps_ref_wraparound_enabled_flag u(1)  if( sps_ref_wraparound_enabled_flag )   sps_ref_wraparound_offset_minus1 ue(v)  sps_temporal_mvp_enabled_flag u(1)  if( sps_temporal_mvp_enabled_flag )   sps_sbtmvp_enabled_flag u(1)  sps_amvr_enabled_flag u(1)  sps_bdof_enabled_flag u(1)  if( sps_bdof_enabled_flag )   sps_bdof_pic_present_flag u(1)  sps_smvd_enabled_flag u(1)  sps_dmvr_enabled_flag u(1)  if( sps_dmvr_enabled_flag)   sps_dmvr_pic_present_flag u(1)  sps_mmvd_enabled_flag u(1)  sps_isp_enabled_flag u(1)  sps_mrl_enabled_flag u(1)  sps_mip_enabled_flag u(1)  if( ChromaArrayType != 0 )   sps_cclm_enabled_flag u(1)   if( sps_cclm_enabled_flag && chroma_format_idc = = 1 )   sps_cclm_colocated_chroma_flag u(1)  sps_mts_enabled_flag u(1)  if( sps_mts_cnabled_flag ) {   sps_explicit_mts_intra_enabled_flag u(1)   sps_explicit_mts_inter_enabled_flag u(1)  }  sps_sbt_enabled_flag u(1)  sps_affine_enabled_flag u(1)  if( sps_affine_enabled_flag ) {   sps_affine_type_flag u(1)   sps_affine_amvr_enabled_flag u(1)   sps_affine_prof_enabled_flag u(1)   if( sps_affine_prof_enabled_flag )    sps_prof_pic_present_flag u(1)  }  if( chroma_format_idc = = 3 ) {   sps_palette_enabled_flag u(1)   sps_act_enabled_flag u(1)  }  sps_bcw_enabled_flag u(1)  sps_ibc_enabled_flag u(1)  sps_ciip_enabled_flag u(1)  if( sps_mmvd_enabled_flag )   sps_fpel_mmvd_enabled_flag u(1)  sps_triangle_enabled_flag u(1)  sps_lmcs_enabled_flag u(1)  sps_lfnst_enabled_flag u(1)  sps_ladf_enabled_flag u(1)  if( sps_ladf_enabled_flag ) {   sps_num_ladf_intervals_minus2 u(2)   sps_ladf_lowest_interval_qp_offset se(v)   for( i = 0; i < sps_num_ladf_intervals_minus2 + 1; i++ ) {    sps_ladf_qp_offset[ i ] se(v)    sps_ladf_delta_threshold_minus1[ i ] ue(v)   }  }  sps_scaling_list_enabled_flag u(1)  sps_loop_filter_across_virtual_boundaries_disabled_ u(1)  present_flag  if( sps_loop_filter_across_virtual_boundaries_  disabled_present_flag ) {   sps_num_ver_virtual_boundaries u(2)   for( i = 0; i < sps_num_ver_virtual_boundaries; i++ )    sps_virtual_boundaries_pos_x[ i ] u(13)   sps_num_hor_virtual_boundaries u(2)   for( i = 0; i < sps_num_hor_virtual_boundaries; i++ )    sps_virtual_boundaries_pos_y[ i ] u(13)  }  if( sps_ptl_dpb_hrd_params_present_flag ) {   sps_general_hrd_params_present_flag u(1)   if( sps_general_hrd_params_present_flag ) {    general_hrd_parameters( )    if( sps_max_sub_layers_minus1 > 0 )     sps_sub_layer_cpb_params_present_flag u(1)    firstSubLayer = sps_sub_layer_cpb_params_    present_flag ? 0 :      sps_max_sub_layers_minus1    ols_hrd_parameters( firstSubLayer,    sps_max_sublayers_minus1 )   }  }  vui_parameters_present_flag u(1)  if( vui_parameters_present_flag )   vui_parameters( )  sps_extension_flag u(1)  if( sps_extension_flag )   while( more_rbsp_data( ) )    sps_extension_data_flag u(1)  rbsp_trailing_bits( ) }

-   -   With respect to Table 3, JVET-P2001 provides the following         semantics:     -   An SPS RBSP shall be available to the decoding process prior to         it being referenced, included in at least one AU with TemporalId         equal to 0 or provided through external means.     -   All SPS NAL units with a particular value of         sps_seq_parameter_set_id in a CVS shall have the same content.     -   sps_decoding_parameter_set_id, when greater than 0, specifies         the value of dps_decoding_parameter_set_id for the DPS referred         to by the SPS. When sps_decoding_parameter_set_id is equal to 0,         the SPS does not refer to a DPS and no DPS is referred to when         decoding each CLVS referring to the SPS. The value of         sps_decoding_parameter_set_id shall be the same in all SPSs that         are referred to by coded pictures in a bitstream.     -   sps_video_parameter_set_id, when greater than 0, specifies the         value of vps_video_parameter_set_id for the VPS referred to by         the SPS.     -   When sps_video_parameter_set_id is equal to 0, the following         applies:         -   The SPS does not refer to a VPS.         -   No VPS is referred to when decoding each CLVS referring to             the SPS.         -   The value of vps_max_layers_minus1 is inferred to be equal             to 0.         -   The CVS shall contain only one layer (i.e., all VCL NAL unit             in the CVS shall have the same value of nuh_layer_id).         -   The value of GeneralLayerIdx[nuh_layer_id] is inferred to be             equal to 0.         -   The value of             vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is             inferred to be equal to 1.     -   When vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]]         is equal to 1, the SPS referred to by a CLVS with a particular         nuh_layer_id value nuhLayerId shall have nuh_layer_id equal to         nuhLayerId.     -   sps_max_sub_layers_minus1 plus 1 specifies the maximum number of         temporal sub-layers that may be present in each CLVS referring         to the SPS. The value of sps_max_sub_layers_minus1 shall be in         the range of 0 to vps_max_sub_layers_minus1, inclusive.     -   sps_reserved_zero_4bits shall be equal to 0 in bitstreams         conforming to this version of this Specification. Other values         for sps_reserved_zero_4bits are reserved for future use by         ITU-T|ISO/IEC.     -   sps_ptl_dpb_hrd_params_present_flag equal to 1 specifies that a         profile_tier_level( ) syntax structure and a dpb_parameters( )         syntax structure are present in the SPS, and a         general_hrd_parameters( ) syntax structure and an         ols_hrd_parameters( ) syntax structure may also be present in         the SPS. sps_ptl_dpb_hrd_params_present_flag equal to 0         specifies that none of these syntax structures is present in the         SPS. The value of sps_ptl_dpb_hrd_params_present_flag shall be         equal to vps_independent_layer_flag[nuh_layer_id].     -   If vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is         equal to 1, the variable MaxDecPicBuffMinus1 is set equal to         max_dec_pic_buffering_minus1[sps_max_sub_layers_minus1] in the         dpb_parameters( ) syntax structure in the SPS. Otherwise,         MaxDecPicBuffMinus1 is set equal to         max_dec_pic_buffering_minus1[sps_max_sub_layers_minus1] in the         layer_nonoutput_dpb_params_idx[GeneralLayerIdx[nuh_layer_id]]-th         dpb_parameters( ) syntax structure in the VPS.     -   gdr_enabled_flag equal to 1 specifies that GDR pictures may be         present in CLVSs referring to the SPS. gdr_enabled_flag equal to         0 specifies that GDR pictures are not present in CLVSs referring         to the SPS.     -   spe_seq_paramster_set_id provides an identifier for the SPS for         reference by other syntax elements.     -   SPS NAL units, regardless of the nuh_layer_id values, share the         same value space of sps_seq_parameter_set_id.     -   chroma_format_idc specifies the chroma sampling relative to the         luma sampling.     -   separate_colour_plane_flag equal to 1 specifies that the three         colour components of the 4:4:4 chroma format are coded         separately. separate_colour_plane_flag equal to 0 specifies that         the colour components are not coded separately. When         separate_colour_plane_flag is not present, it is inferred to be         equal to 0. When separate_colour_plane_flag is equal to 1, the         coded picture consists of three separate components, each of         which consists of coded samples of one colour plane (Y, Cb, or         Cr) and uses the monochrome coding syntax. In this case, each         colour plane is associated with a specific colour_plane_id         value.         -   NOTE—There is no dependency in decoding processes between             the colour planes having different colour_plane_id values.             For example, the decoding process of a monochrome picture             with one value of colour_plane_id does not use any data from             monochrome pictures having different values of             colour_plane_id for inter prediction.     -   Depending on the value of separate_colour_plane_flag, the value         of the variable ChromaArrayType is assigned as follows:         -   If separate_colour_plane_flag is equal to 0, ChromaArrayType             is set equal to chroma_format_idc.         -   Otherwise (separate_colour_plane_flag is equal to 1),             ChromaArrayType is set equal to 0.     -   ref_pic_resampling_enabled_flag equal to 1 specifies that         reference picture resampling may be applied when decoding coded         pictures in the CLVSs referring to the SPS.         ref_pic_resampling_enabled_flag equal to 0 specifies that         reference picture resampling is not applied when decoding         pictures in CLVSs referring to the SPS.     -   pic_width_max_in_luma_samples specifies the maximum width, in         units of luma samples, of each decoded picture referring to the         SPS. pic_width_max_in_luma_samples shall not be equal to 0 and         shall be an integer multiple of Max(8, MinCbSizeY).     -   pic_height_max_in_luma_samples specifies the maximum height, in         units of luma samples, of each decoded picture referring to the         SPS. pic_height_max_in_luma_samples shall not be equal to 0 and         shall be an integer multiple of Max(8, MinCbSizeY).     -   sps_log2_ctu_size_minus5 plus 5 specifies the luma coding tree         block size of each CTU. It is a requirement of bitstream         conformance that the value of sps_log2_ctu_size_minus5 be less         than or equal to 2.     -   The variables CtbLog2SizeY and CtbSizeY are derived as follows:

CtbLog2SizeY=sps_log2_ctu_size_minus5+5

CtbSizeY=1<<CtbLog2SizeY

-   -   subpics_present_flag equal to 1 indicates that subpicture         parameters are present in the present in the SPS RBSP syntax.         subpics_present_flag equal to 0 indicates that subpicture         parameters are not present in the present in the SPS RBSP         syntax.         -   NOTE—When a bitstream is the result of a sub-bitstream             extraction process and contains only a subset of the             subpictures of the input bitstream to the sub-bitstream             extraction process, it might be required to set the value of             subpics_present_flag equal to 1 in the RBSP of the SPSs.     -   sps_num_subpic_minus1 plus 1 specifies the number of         subpictures. sps_num_subpics_minus1 shall be in the range of 0         to 254. When not present, the value of sps_num_subpics_minus1 is         inferred to be equal to 0.     -   subpic_ctu_top_left_x[i] specifies horizontal position of top         left CTU of i-th subpicture in unit of CtbSizeY. The length of         the syntax element is         Ceil(Log2(pic_width_max_in_luma_samples/CtbSizeY)) bits. When         not present, the value of subpic_ctu_top_left_x[i] is inferred         to be equal to 0.     -   subpic_ctu_top_left_y[i] specifies vertical position of top left         CTU of i-th subpicture in unit of CtbSizeY. The length of the         syntax element is         Ceil(Log2(pic_height_max_in_luma_samples/CtbSizeY)) bits. When         not present, the value of subpic_ctu_top_left_y[i] is inferred         to be equal to 0.     -   subpic_width_minus1[i] plus 1 specifies the width of the i-th         subpicture in units of CtbSizeY. The length of the syntax         element is Ceil(Log2(pic_width_max_in_luma_samples/CtbSizeY))         bits. When not present, the value of subpic_width_minus1[i] is         inferred to be equal to         Ceil(pic_width_max_in_luma_samples/CtbSizeY)−1.     -   subpic_height_minus1[i] plus 1 specifies the height of the i-th         subpicture in units of CtbSizeY. The length of the syntax         element is Ceil(Log2(pic_height_max_in_luma_samples/CtbSizeY))         bits. When not present, the value of subpic_height_minus1[i] is         inferred to be equal to         Ceil(pic_height_max_in_luma_samples/CtbSizeY)−1.     -   subpic_treated_as_pic_flag[i] equal to 1 specifies that the i-th         subpicture of each coded picture in the CLVS is treated as a         picture in the decoding process excluding in-loop filtering         operations. subpic_treated_as_pic_flag[i] equal to 0 specifies         that the i-th subpicture of each coded picture in the CLVS is         not treated as a picture in the decoding process excluding         in-loop filtering operations. When not present, the value of         subpic_treated_as_pic_flag[i] is inferred to be equal to 0.     -   loop_filter_across_subpic_enabled_flag[i] equal to 1 specifies         that in-loop filtering operations may be performed across the         boundaries of the i-th subpicture in each coded picture in the         CLVS. loop_filter_across_subpic_enabled_flag[i] equal to 0         specifies that in-loop filtering operations are not performed         across the boundaries of the i-th subpicture in each coded         picture in the CLVS. When not present, the value of         loop_filter_across_subpic_enabled_pic_flag[i] is inferred to be         equal to 1.     -   It is a requirement of bitstream conformance that the following         constraints apply:         -   For any two subpictures subpicA and subpicB, when the index             of subpicA is less than the index of subpicB, any coded NAL             unit of subPicA shall succeed any coded NAL unit of subPicB             in decoding order.         -   The shapes of the subpictures shall be such that each             subpicture, when decoded, shall have its entire left             boundary and entire top boundary consisting of picture             boundaries or consisting of boundaries of previously decoded             subpictures.     -   sps_subpic_id_present_flag equal to 1 specifies that subpicture         ID mapping is present in the SPS. sps_subpic_id_present_flag         equal to 0 specifies that subpicture ID mapping is not present         in the SPS.     -   sps_subpic_id_signalling_present_flag equal to 1 specifies that         subpicture ID mapping is signalled in the SPS.         sps_subpic_id_signalling_present_flag equal to 0 specifies that         subpicture ID mapping is not signalled in the SPS. When not         present, the value of sps_subpic_id_signalling_present_flag is         inferred to be equal to 0.     -   sps_subpic_id_len_minus1 plus 1 specifies the number of bits         used to represent the syntax element sps_subpic_id[i]. The value         of sps_subpic_id_len_minus1 shall be in the range of 0 to 15,         inclusive.     -   sps_subpic_id[i] specifies that subpicture ID of the i-th         subpicture. The length of the sps_subpic_id[i] syntax element is         sps_subpic_id_len_minus1+1 bits. When not present, and when         sps_subpic_id_present_flag equal to 0, the value of         sps_subpic_id[i] is inferred to be equal to i, for each i in the         range of 0 to sps_num_subpics_minus1, inclusive     -   bit_depth_minus8 specifies the bit depth of the samples of the         luma and chroma arrays, BitDepth, and the value of the luma and         chroma quantization parameter range offset, QpBdOffset, as         follows:

BitDepth=8+bit_depth_minus8

QpBdOffset=6*bit_depth_minus8

-   -   bit_depth_minus8 shall be in the range of 0 to 8, inclusive.     -   min_qp_prime_ts_minus4 specifies the minimum allowed         quantization parameter for transform skip mode as follows:

QpPrimeTsMin=4+min_qp_prime_ts_minus4

-   -   The value of min_qp_prime_ts_minus4 shall be in the range of 0         to 48, inclusive.     -   sps_weighted_pred_flag equal to 1 specifies that weighted         prediction may be applied to P slices referring to the SPS.         sps_weighted_pred_flag equal to 0 specifies that weighted         prediction is not applied to P slices referring to the SPS.     -   sps_weighted_bipred_flag equal to 1 specifies that explicit         weighted prediction may be applied to B slices referring to the         SPS. sps_weighted_bipred_flag equal to 0 specifies that explicit         weighted prediction is not applied to B slices referring to the         SPS.     -   log2_max_pic_order_cnt_lsb_minus4 specifies the value of the         variable MaxPicOrderCntLsb that is used in the decoding process         for picture order count as follows:

MaxPicOrderCntLsb=2^((log2_max_pic_order_cnt_lsb_minus4+4))

-   -   The value of log2_max_pic_order_cnt_lsb_minus4 shall be in the         range of 0 to 12, inclusive.     -   sps_poc_msb_flag equal to 1 specifies that the         ph_poc_msb_cycle_present_flag syntax element is present in PHs         referring to the SPS. sps_poc_msb_flag equal to 0 specifies that         the ph_poc_msb_cycle_present_flag syntax element is not present         in PHs referring to the SPS.     -   poc_msb_len_minu1 plus 1 specifies the length, in bits, of the         poc_msb_val syntax elements, when present in the PHs referring         to the SPS. The value of poc_msb_len_minus1 shall be in the         range of 0 to 32−log2_max_pic_order_cnt_lsb_minus4−5, inclusive.     -   sps_sub_layer_dpb_params_flag is used to control the presence of         max_dec_pic_buffering_minus1[i], max_num_reorder_pics[i], and         max_latency_increase_plus1[i] syntax elements in the         dpb_parameters( ) syntax structure in the SPS. When not present,         the value of sps_sub_dpb_params_info_present_flag is inferred to         be equal to 0.     -   long_term_ref_pics_flag equal to 0 specifies that no LTRP is         used for inter prediction of any coded picture in the CLVS.         long_term_ref_pics_flag equal to 1 specifies that LTRPs may be         used for inter prediction of one or more coded pictures in the         CLVS.     -   inter_layer_ref_pics_present_flag equal to 0 specifies that no         ILRP is used for inter prediction of any coded picture in the         CLVS. inter_layer_ref_pics_flag equal to 1 specifies that ILRPs         may be used for inter prediction of one or more coded pictures         in the CLVS. When sps_video_parameter_set_id is equal to 0, the         value of inter_layer_ref_pics_present_flag is inferred to be         equal to 0. When         vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is         equal to 1, the value of inter_layer_ref_pic_present_flag shall         be equal to 0.     -   sps_idr_rpl_present_flag equal to 1 specifies that reference         picture list syntax elements are present in slice headers of IDR         pictures. sps_idr_rpl_present_flag equal to 0 specifies that         reference picture list syntax elements are not present in slice         headers of IDR pictures.     -   rpl1_same_as_rpl0_flag equal to 1 specifies that the syntax         element num_ref_pic_lists_in_sps[1] and the syntax structure         ref_pic_list_struct(1, rplsIdx) are not present and the         following applies:         -   The value of num_ref_pic_lists_in_sps[1] is inferred to be             equal to the value of num_ref_pic_lists_in_sps[0].         -   The value of each of syntax elements in             ref_pic_list_struct(1, rplsIdx) is inferred to be equal to             the value of corresponding syntax element in             ref_pic_list_struct(0, rplsIdx) for rplsIdx ranging from 0             to num_ref_pic_lists_in_sps[0]−1.     -   num_ref_pic_lists_in_sps[i] specifies the number of the         ref_pic_list_struct(listIdx, rplsIdx) syntax structures with         listIdx equal to i included in the SPS. The value of         num_ref_pic_lists_in_sps[i] shall be in the range of 0 to 64,         inclusive.         -   NOTE—For each value of listIdx (equal to 0 or 1), a decoder             should allocate memory for a total number of             num_ref_pic_lists_in_sps[i]+1 ref_pic_list_sruct(listIdx,             rplsIdx) syntax structures since there may be one             ref_pic_list_struct(listIdx, rplsIdx) syntax structure             directly signalled in the slice headers of a current             picture.     -   qtt_dual_tree_intra_flag equal to 1 specifies that for I slices,         each CTU is split into coding units with 64×64 luma samples         using an implicit quadtree split and that these coding units are         the root of two separate coding_tree syntax structure for luma         and chroma. qtbtt_dual_tree_intra_flag equal to 0 specifies         separate coding_tree syntax structure is not used for I slices.         When qtbtt_dual_tree_intra_flag is not present, it is inferred         to be equal to 0.     -   log2_min_luma_coding_block_size_minus2 plus 2 specifies the         minimum luma coding block size. The value range of         log2_min_luma_coding_block_size_minus2 shall be in the range of         0 to log2_ctu_size_minus5+3, inclusive.     -   The variables MinCbLog2SizeY, MinCbSizeY, IbcBufWidthY,         IbcBufWidthC and Vsize are derived as follows:

MinCbLog2SizeY=log2_min_luma_coding_block_size_minus2+2

MinCbSizeY=1<<MinCbLog2SizeY

IbcBufWidthY=256*128/CtbSizeY

IbcBufWidthC=IbcBufWidthY/SubWidthC

VSize=Min(64,CtbSizeY)

-   -   The value of MinCbSizeY shall less than or equal to VSize.     -   The variables CtbWidthC and CtbHeightC, which specify the width         and height, respectively, of the array for each chroma CTB, are         derived as follows:         -   If chroma_format_idc is equal to 0 (monochrome) or             separate_colour_plane_flag is equal to 1, CtbWidthC and             CtbHeightC are both equal to 0.         -   Otherwise, CtbWidthC and CtbHeightC are derived as follows:

CtbWidthC=CtbSizeY/SubWidthC

CtbHeightC=CtbSizeY/SubHeightC

-   -   For log2BlockWidth ranging from 0 to 4 and for log2BlockHeight         ranging from 0 to 4, inclusive, the up-right diagonal and raster         scan order array initialization process as specified is invoked         with 1<<log2BlockWidth and 1<<log2BlockHeight as inputs, and the         output is assigned to DiagScanOrder[log2BlockWidth         ][log2BlockHeight] and         Raster2DiagScanPos[log2BlockWidth][log2BlockHeight].     -   For log2BlockWidth ranging from 0 to 6 and for log2BlockHeight         ranging from 0 to 6, inclusive, the horizontal and vertical         traverse scan order array initialization process as specified is         invoked with 1<<log2BlockWidth and 1<<log2BlockHeight as inputs,         and the output is assigned to         HorTravScanOrder[log2BlockWidth][log2BlockHeight] and         VerTravScanOrder[log2BlockWidth][log2BlockHeight].     -   partition_constraints_override_enabled_flag equal to 1 specifies         the presence of partition_constraints_override_flag in PHs         referring to the SPS.         partition_constraints_override_enabled_flag equal to 0 specifies         the absence of partition_constraints_override_flag in PHs         referring to the SPS.     -   sps_log2_diff_min_qt_min_cb_intra_slice_luma specifies the         default difference between the base 2 logarithm of the minimum         size in luma samples of a luma leaf block resulting from         quadtree splitting of a CTU and the base 2 logarithm of the         minimum coding block size in luma samples for luma CUs in slices         with slice_type equal to 2 (I) referring to the SPS. When         partition_constraints_override_enabled_flag is equal to 1, the         default difference can be overridden by         pic_log2_diff_min_qt_min_cb_luma present in PHs referring to the         SPS. The value of sps_log2_diff_min_qt_min_cb_intra_slice_luma         shall be in the range of 0 to CtbLog2SizeY−MinCbLog2SizeY,         inclusive. The base 2 logarithm of the minimum size in luma         samples of a luma leaf block resulting from quadtree splitting         of a CTU is derived as follows:

MinQtLog2SizeIntraY−sps_log2_diff_min_qt_min_cb_intra_slice_luma+MinCbLog2SizeY

-   -   sps_log2_diff_min_qt_min_cb_inter_slice specifies the default         difference between the base 2 logarithm of the minimum size in         luma samples of a luma leaf block resulting from quadtree         splitting of a CTU and the base 2 logarithm of the minimum luma         coding block size in luma samples for luma CUs in slices with         slice_type equal to 0 (B) or 1 (P) referring to the SPS. When         partition_constraints_override_enabled_flag is equal to 1, the         default difference can be overridden by         pic_log2_diff_min_qt_min_cb_luma present in PHs referring to the         SPS. The value of sps_log2_diff_min_qt_min_cb_inter_slice shall         be in the range of 0 to CtbLog2SizeY−MinCbLog2SizeY, inclusive.         The base 2 logarithm of the minimum size in luma samples of a         luma leaf block resulting from quadtree splitting of a CTU is         derived as follows:

MinQtLog2SizeInterY=sps_log2_diff_min_qt_min_cb_inter_slice+MinCbLog2SizeY

-   -   sps_max_mtt_hierarchy_depth_inter_slice specifies the default         maximum hierarchy depth for coding units resulting from         multi-type tree splitting of a quadtree leaf in slices with         slice_type equal to 0 (B) or 1 (P) referring to the SPS. When         partition_constraints_override_enabled_flag is equal to 1, the         default maximum hierarchy depth can be overridden by         pic_max_mtt_hierarchy_depth_inter_slice present in PHs referring         to the SPS. The value of sps_max_mtt_hierarchy_depth_inter_slice         shall be in the range of 0 to CtbLog2SizeY−MinCbLog2SizeY,         inclusive.     -   sps_max_mtt_hierarchy_depth_intra_slice_luma specifies the         default maximum hierarchy depth for coding units resulting from         multi-type tree splitting of a quadtree leaf in slices with         slice_type equal to 2 ( ) referring to the SPS. When         partition_constraints_override_enabled_flag is equal to 1, the         default maximum hierarchy depth can be overridden by         pic_max_mtt_hierarchy_depth_intra_slice_luma present in PHs         referring to the SPS. The value of         sps_max_mtt_hierarchy_depth_intra_slice_luma shall be in the         range of 0 to CtbLog2SizeY−MinCbLog2SizeY, inclusive.     -   sps_log2_diff_max_bt_min_qt_intra_slice_luma specifies the         default difference between the base 2 logarithm of the maximum         size (width or height) in luma samples of a luma coding block         that can be split using a binary split and the minimum size         (width or height) in luma samples of a luma leaf block resulting         from quadtree splitting of a CTU in slices with slice_type equal         to 2 ( ) referring to the SPS. When         partition_constraints_override_enabled_flag is equal to 1, the         default difference can be overridden by         pic_log2_diff_max_bt_min_qt_luma present in PHs referring to the         SPS. The value of sps_log2_diff_max_bt_min_qt_intra_slice_luma         shall be in the range of 0 to CtbLog2SizeY−MinQtLog2SizeIntraY,         inclusive. When sps_log2_diff_max_bt_min_qt_intra_slice_luma is         not present, the value of         sps_log2_diff_max_bt_min_qt_intra_slice_luma is inferred to be         equal to 0.     -   sps_log2_diff_max_tt_min_qt_intra_slice_luma specifies the         default difference between the base 2 logarithm of the maximum         size (width or height) in luma samples of a luma coding block         that can be split using a ternary split and the minimum size         (width or height) in luma samples of a luma leaf block resulting         from quadtree splitting of a CTU in slices with slice_type equal         to 2 (I) referring to the SPS. When         partition_constraints_override_enabled_flag is equal to 1, the         default difference can be overridden by         pic_log2_diff_max_tt_min_qt_luma present in PHs referring to the         SPS. The value of sps_log2_diff_max_tt_min_qt_intra_slice_luma         shall be in the range of 0 to CtbLog2SizeY−MinQtLog2SizeIntraY,         inclusive. When sps_log2_diff_max_tt_min_qt_intra_slice_luma is         not present, the value of         sps_log2_diff_max_tt_min_qt_intra_slice_luma is inferred to be         equal to 0.     -   sps_log2_diff_max_bt_min_qt_inter_slice specifies the default         difference between the base 2 logarithm of the maximum size         (width or height) in luma samples of a luma coding block that         can be split using a binary split and the minimum size (width or         height) in luma samples of a luma leaf block resulting from         quadtree splitting of a CTU in slices with slice_type equal to         0 (B) or 1 (P) referring to the SPS. When         partition_constraints_override_enabled_flag is equal to 1, the         default difference can be overridden by         pic_log2_diff_max_bt_min_qt_luma present in PHs referring to the         SPS. The value of sps_log2_diff_max_bt_min_qt_inter_slice shall         be in the range of 0 to CtbLog2SizeY−MinQtLog2SizeInterY,         inclusive. When sps_log2_diff_max_bt_min_qt_inter_slice is not         present, the value of sps_log2_diff_max_bt_min_qt_inter_slice is         inferred to be equal to 0.     -   sps_log2_diff_max_bt_min_qt_inter_slice specifies the default         difference between the base 2 logarithm of the maximum size         (width or height) in luma samples of a luma coding block that         can be split using a ternary split and the minimum size (width         or height) in luma samples of a luma leaf block resulting from         quadtree splitting of a CTU in slices with slice_type equal to         0 (B) or 1 (P) referring to the SPS. When         partition_constraints_override_enabled_flag is equal to 1, the         default difference can be overridden by         pic_log2_diff_max_tt_min_qt_luma present in PHs referring to the         SPS. The value of sps_log2_diff_max_tt_min_qt_inter_slice shall         be in the range of 0 to CtbLog2SizeY−MinQtLog2SizeInterY,         inclusive. When sps_log2_diff_max_tt_min_qt_inter_slice is not         present, the value of sps_log2_diff_max_tt_min_qt_inter_slice is         inferred to be equal to 0.     -   sps_log2_diff_min_qt_min_cb_intra_slice_chroma specifies the         default difference between the base 2 logarithm of the minimum         size in luma samples of a chroma leaf block resulting from         quadtree splitting of a chroma CTU with treeType equal to         DUAL_TREE_CHROMA and the base 2 logarithm of the minimum coding         block size in luma samples for chroma CUs with treeType equal to         DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I)         referring to the SPS. When         partition_constraints_override_enabled_flag is equal to 1, the         default difference can be overridden by         pic_log2_diff_min_qt_min_cb_chroma present in PHs referring to         the SPS. The value of         sps_log2_diff_min_qt_min_cb_intra_slice_chroma shall be in the         range of 0 to CtbLog2SizeY−MinCbLog2SizeY, inclusive. When not         present, the value of         sps_log2_diff_min_qt_min_cb_intra_slice_chroma is inferred to be         equal to 0. The base 2 logarithm of the minimum size in luma         samples of a chroma leaf block resulting from quadtree splitting         of a CTU with treeType equal to DUAL_TREE_CHROMA is derived as         follows:

MinQtLog2SizeIntraC=sps_log2_diff_min_qt_min_cb_intra_slice_chroma+MinCbLog2SizeY

-   -   sps_max_mtt_hierarcy_depth_intra_slice_chroma specifies the         default maximum hierarchy depth for chroma coding units         resulting from multi-type tree splitting of a chroma quadtree         leaf with treeType equal to DUAL_TREE_CHROMA in slices with         slice_type equal to 2 (I) referring to the SPS. When         partition_constraints_override_enabled_flag is equal to 1, the         default maximum hierarchy depth can be overridden by         pic_max_mtt_hierarchy_depth_chroma present in PHs referring to         the SPS. The value of         sps_max_mtt_hierarchy_depth_intra_slice_chroma shall be in the         range of 0 to CtbLog2SizeY−MinCbLog2SizeY, inclusive. When not         present, the value of         sps_max_mtt_hierarchy_depth_intra_slice_chroma is inferred to be         equal to 0.     -   sps_log2_diff_max_bt_min_qt_intra_slice_chroma specifies the         default difference between the base 2 logarithm of the maximum         size (width or height) in luma samples of a chroma coding block         that can be split using a binary split and the minimum size         (width or height) in luma samples of a chroma leaf block         resulting from quadtree splitting of a chroma CTU with treeType         equal to DUAL_TREE_CHROMA in slices with slice_type equal to         2 (I) referring to the SPS. When partition         constraints_override_enabled_flag is equal to 1, the default         difference can be overridden by         pic_log2_diff_max_bt_min_qt_chroma present in PHs referring to         the SPS. The value of         sps_log2_diff_max_bt_min_qt_intra_slice_chroma shall be in the         range of 0 to CtbLog2SizeY−MinQtLog2SizeIntraC, inclusive. When         sps_log2_diff_max_bt_min_qt_intra_slice_chroma is not present,         the value of sps_log2_diff_max_bt_min_qt_intra_slice_chroma is         inferred to be equal to 0.     -   sps_log2_diff_max_tt_min_qt_intra_slice_chroma specifies the         default difference between the base 2 logarithm of the maximum         size (width or height) in luma samples of a chroma coding block         that can be split using a ternary split and the minimum size         (width or height) in luma samples of a chroma leaf block         resulting from quadtree splitting of a chroma CTU with treeType         equal to DUAL_TREE_CHROMA in slices with slice_type equal to         2 (I) referring to the SPS. When         partition_constraints_override_enabled_flag is equal to 1, the         default difference can be overridden by         pic_log2_diff_max_tt_min_qt_chroma present in PHs referring to         the SPS. The value of         sps_log2_diff_max_tt_min_qt_intra_slice_chroma shall be in the         range of 0 to CtbLog2SizeY−MinQtLog2SizeIntraC, inclusive. When         sps_log2_diff_max_tt_min_qt_intra_slice_chroma is not present,         the value of sps_log2_diff_max_tt_min_qt_intra_slice_chroma is         inferred to be equal to 0.     -   sps_max_luma_transform_size_64_flag equal to 1 specifies that         the maximum transform size in luma samples is equal to 64.         sps_max_luma_transform_size_64_flag equal to 0 specifies that         the maximum transform size in luma samples is equal to 32.     -   When CtbSizeY is less than 64, the value of         sps_max_luma_transform_size_64_flag shall be equal to 0.     -   The variables MinTbLog2SizeY, MaxTbLog2SizeY, MinTbSizeY, and         MaxTbSizeY are derived as follows:

MinTbLog2SizeY=2

MaxTbLog2SizeY=sps_max_luma_transform_size_64_flag?6:5

MinTbSizeY=1<<MinTbLog2SizeY

MaxTbSizeY=1<<MaxTLog2SizeY

-   -   sps_joint_cbcr_enable_flag equal to 0 specifies that the joint         coding of chroma residuals is disabled.         sps_joint_cbcr_enabled_flag equal to 1 specifies that the joint         coding of chroma residuals is enabled.     -   same_qp_table_or_chroma equal to 1 specifies that only one         chroma QP mapping table is signalled and this table applies to         Cb and Cr residuals as well as joint Cb-Cr residuals.         same_qp_table_for_chroma equal to 0 specifies that three chroma         QP mapping tables are signalled in the SPS. When         same_qp_table_for_chroma is not present in the bitstream, the         value of same_qp_table_for_chroma is inferred to be equal to 1.     -   qp_table_start_minus26[i] plus 26 specifies the starting luma         and chroma QP used to describe the i-th chroma QP mapping table.         The value of qp_table_start_minus26[i] shall be in the range of         −26−QpBdOffsetC to 36 inclusive. When qp_table_start_minus26[i]         is not present in the bitstream, the value of         qp_table_start_minus26[i] is inferred to be equal to 0.     -   num_points_in_qp_table_minus1[i] plus 1 specifies the number of         points used to describe the i-th chroma QP mapping table. The         value of num_points_in_qp_table_minus1[i] shall be in the range         of 0 to 63+QpBdOffset, inclusive. When         num_points_in_qp_table_minus1[0] is not present in the         bitstream, the value of num_points_in_qp_table_minus1[0] is         inferred to be equal to 0.     -   delta_qt_in_val_minu1[i][j] specifies a delta value used to         derive the input coordinate of the j-th pivot point of the i-th         chroma QP mapping table. When delta_qp_in_val_minus1[0][j] is         not present in the bitstream, the value of         delta_qp_in_val_minus1[0][j] is inferred to be equal to 0.     -   delta_qp_diff_val[i][j] specifies a delta value used to derive         the output coordinate of the j-th pivot point of the i-th chroma         QP mapping table. When delta_qp_out_val[0][j] is not present in         the bitstream, the value of delta_qp_out_val[0][j] is inferred         to be equal to 0.     -   The i-th chroma QP mapping table ChromaQpTable[i] for i=0 . . .         same_qp_table_for_chroma?0:2 is derived as follows:

  qpInVal[ i ][ 0 ] = −qp_table_start_minus26[ i ] + 26 qpOutVal[ i ][ 0 ] = qpInVal[ i ][ 0 ] for( j = 0; j <= num_points_in_qp_table_minus1[ i ] j++ ) {  qpInVal[ i ][ j + 1 ] = qpInVal[ i ][ j ] + delta_qp_in_val_minus1[ i ][ j ] + 1  qpOutVal[ i ][ j + 1 ] = qpOutVal[ i ][ j ] + ( delta_qp_in_val_minus1[ i ][ j ] {circumflex over ( )} delta_qp_diff_val[ i ][ j ] ) } ChromaQpTable[ i ][ qpInVal[ i ][ 0 ] ] = qpOutVal[ i ][ 0 ] for( k = qpInVal[ i ][ 0 ] − 1; k >= −QpBdOffset; k − − )  ChromaQpTable[ i ][ k ] = Clip3( −QpBdOffset,   63, ChromaQpTable[ i ][ k + 1 ] − 1 ) for( j = 0; j <+ num_points_in_qp_table_minus1[ i ]; j++ ) {  sh = ( delta_qp_in_val_minus1[ i ][j ] + 1 ) >> 1  for( k = qpInVal[ i ][ j ] + 1, m = 1; k <= qpInval[ i ][ j + 1 ]; k++, m++ )   ChromaQpTable[ i ][ k ] = ChromaQpTable[ i ][ qpInVal[ i ][ j ] ] +   ( ( qpOutVal[ i ][j + 1] − qpOutVal[ i ][j ] ) * m + sh ) / ( delta_qp_in_val_minus1[ i ][j] + 1 ) } for( k = qpInVal[ i ][ num_points_in_qp_table_minus1 [ i ] + 1 ] + 1; k <= 63; k++ )  ChromaQpTable[ i ][ k ] = Clip3( −QpBdOffset,   63, ChromaQpTable[ i ][ k − 1 ) + 1 )

-   -   When same_qp_table_for_chroma is equal to 1, ChromaQpTable[1][k]         and ChromaQpTable[2][k] are set equal to ChromaQpTable[0][k] for         k=−QpBdOffset . . . 63.     -   It is a requirement of bitstream conformance that the values of         qpInVal[i][j] and qpOutVal[i][j] shall be in the range of         −QpBdOffset to 63, inclusive for i=0 . . .         same_qp_table_for_chroma? 0:2 and j=0 . . .         num_points_in_qp_table_minus1[i]+1.     -   sps_sao_enabled_flag equal to 1 specifies that the sample         adaptive offset process is applied to the reconstructed picture         after the deblocking filter process. sps_sao_enabled_flag equal         to 0 specifies that the sample adaptive offset process is not         applied to the reconstructed picture after the deblocking filter         process.     -   sps_alf_enabled_flag equal to 0 specifies that the adaptive loop         filter is disabled. sps_alf_enabled_flag equal to 1 specifies         that the adaptive loop filter is enabled.     -   sps_transform_skip_enabled_flag equal to 1 specifies that         transform_skip_flag may be present in the transform unit syntax.         sps_transform_skip_enabled_flag equal to 0 specifies that         transform_skip_flag is not present in the transform unit syntax     -   sps_bdpcm_enable_flag equal to 1 specifies that         intra_bdpcm_luma_flag may be present in the coding unit syntax         for intra coding units. sps_bdpcm_enabled_flag equal to 0         specifies that intra_bdpcm_luma_flag is not present in the         coding unit syntax for intra coding units. When not present, the         value of sps_bdpcm_enabled_flag is inferred to be equal to 0.     -   sps_bdpcm_chroma_enabled_flag equal to 1 specifies that         intra_bdpcm_chroma_flag may be present in the coding unit syntax         for intra coding units. sps_bdpcm_chroma_enabled_flag equal to 0         specifies that intra_bdpcm_chroma_flag is not present in the         coding unit syntax for intra coding units. When not present, the         value of sps_bdpcm_chroma_enabled_flag is inferred to be equal         to 0.     -   sps_ref_wraparound_enabled_flag equal to 1 specifies that         horizontal wrap-around motion compensation is applied in inter         prediction. sps_ref_wraparound_enabled_flag equal to 0 specifies         that horizontal wrap-around motion compensation is not applied.         When the value of (CtbSizeY/MinCbSizeY+1) is less than or equal         to (pic_width_in_luma_samples/MinCbSizeY−1), where         pic_width_in_luma_samples is the value of         pic_width_in_luma_samples in any PPS that refers to the SPS, the         value of sps_ref_wraparound_enabled_flag shall be equal to 0.     -   sps_ref_wraparound_offset_minus1 plus 1 specifies the offset         used for computing the horizontal wrap-around position in units         of MinCbSizeY luma samples. The value of         ref_wraparound_offset_minus1 shall be in the range of         (CtbSizeY/MinCbSizeY)+1 to         (pic_width_in_luma_samples/MinCbSizeY)−1, inclusive, where         pic_width_in_luma_samples is the value of         pic_width_in_luma_samples in any PPS that refers to the SPS.     -   sps_temporoal_mvp_enabled_flag equal to 1 specifies that         temporal motion vector predictors may be used in the CLVS.         sps_temporal_mvp_enabled_flag equal to 0 specifies that temporal         motion vector predictors are not used in the CLVS.     -   sps_sbtmvp_enabled_flag equal to 1 specifies that subblock-based         temporal motion vector predictors may be used in decoding of         pictures with all slices having slice_type not equal to I in the         CLVS. sps_sbtmvp_enabled_flag equal to 0 specifies that         subblock-based temporal motion vector predictors are not used in         the CLVS. When sps_sbtmvp_enabled_flag is not present, it is         inferred to be equal to 0.     -   sps_amvr_enabled_flag equal to 1 specifies that adaptive motion         vector difference resolution is used in motion vector coding.         amvr_enabled_flag equal to 0 specifies that adaptive motion         vector difference resolution is not used in motion vector         coding.     -   sps_bdof_enabled_flag equal to 0 specifies that the         bi-directional optical flow inter prediction is disabled.         sps_bdof_enabled_flag equal to 1 specifies that the         bi-directional optical flow inter prediction is enabled.     -   sps_bdof_pic_present_flag equal to 1 specifies that         pic_disable_bdof_flag is present in PHa referring to the SPS.         sps_bdof_pic_present_flag equal to 0 specifies that         pic_disable_bdof_flag is not present in PHs referring to the         SPS. When sps_bdof_pic_present_flag is not present, the value of         sps_bdof_pic_present_flag is inferred to be equal to 0.     -   sps_smvd_enabled_flag equal to 1 specifies that symmetric motion         vector difference may be used in motion vector decoding.         sps_smvd_enabled_flag equal to 0 specifies that symmetric motion         vector difference is not used in motion vector coding.     -   sps_dmvr_enabled_flag equal to 1 specifies that decoder motion         vector refinement based inter bi-prediction is enabled.         sps_dmvr_enabled_flag equal to 0 specifies that decoder motion         vector refinement based inter bi-prediction is disabled.     -   sps_dmvr_pic_presnt_flag equal to 1 specifies that         pic_disable_dmvr_flag is present in PHs referring to the SPS.         sps_dmvr_pic_present_flag equal to 0 specifies that         pic_disable_dmvr_flag is not present in PHs referring to the         SPS. When sps_dmvr_pic_present_flag is not present, the value of         sps_dmvr_pic_present_flag is inferred to be equal to 0.     -   sps_mmvd_enabled_flag equal to 1 specifies that merge mode with         motion vector difference is enabled. sps_mmvd_enabled_flag equal         to 0 specifies that merge mode with motion vector difference is         disabled.     -   sps_isp_enabled_flag equal to 1 specifies that intra prediction         with subpartitions is enabled. sps_isp_enabled_flag equal to 0         specifies that intra prediction with subpartitions is disabled.     -   sps_mrl_enabled_flag equal to 1 specifies that intra prediction         with multiple reference lines is enabled. sps_mrl_enabled_flag         equal to 0 specifies that intra prediction with multiple         reference lines is disabled.     -   sps_mip_enabled_flag equal to 1 specifies that matrix-based         intra prediction is enabled. sps_mip_enabled_flag equal to 0         specifies that matrix-based intra prediction is disabled.     -   sps_cclm_enabled_flag equal to 0 specifies that the         cross-component linear model intra prediction from luma         component to chroma component is disabled. sps_cclm_enabled_flag         equal to 1 specifies that the cross-component linear model intra         prediction from luma component to chroma component is enabled.         When sps_cclm_enabled_flag is not present, it is inferred to be         equal to 0.     -   sps_cclm_colocated_chroma_flag equal to 1 specifies that the         top-left downsampled luma sample in cross-component linear model         intra prediction is collocated with the top-left luma sample.         sps_cclm_colocated_chroma_flag equal to 0 specifies that the         top-left downsampled luma sample in cross-component linear model         intra prediction is horizontally co-sited with the top-left luma         sample but vertically shifted by 0.5 units of luma samples         relatively to the top-left luma sample.     -   sps_mts_enabled_flag equal to 1 specifies that         sps_explicit_mts_intra_enabled_flag is present in the sequence         parameter set RBSP syntax and that         sps_explicit_mts_inter_enabled_flag is present in the sequence         parameter set RBSP syntax. sps_mts_enabled_flag equal to 0         specifies that sps_explicit_mts_intra_enabled_flag is not         present in the sequence parameter set RBSP syntax and that         sps_explicit_mts_inter_enabled_flag is not present in the         sequence parameter set RBSP syntax.     -   sps_explicit_mts_intra_enabled_flag equal to 1 specifies that         mts_idx may be present in intra coding unit syntax.         sps_explicit_mts_intra_enabled_flag equal to 0 specifies that         mts_idx is not present in intra coding unit syntax. When not         present, the value of sps_explicit_mts_intra_enabled_flag is         inferred to be equal to 0.     -   sps_explicit_mts_inter_enabled_flag equal to 1 specifies that         mts_idx may be present in inter coding unit syntax.         sps_explicit_mts_inter_enabled_flag equal to 0 specifies that         mts_idx is not present in inter coding unit syntax. When not         present, the value of sps_explicit_mts_inter_enabled_flag is         inferred to be equal to 0.     -   sps_sbt_enabled_flag equal to 0 specifies that subblock         transform for inter-predicted CUs is disabled.         sps_sbt_enabled_flag equal to 1 specifies that subblock         transform for inter-predicteds CU is enabled.     -   sps_affine_enabled_flag specifies whether affine model based         motion compensation can be used for inter prediction. If         sps_affine_enabled_flag is equal to 0, the syntax shall be         constrained such that no affine model based motion compensation         is used in the CLVS, and inter_affine_flag and         cu_affine_type_flag are not present in coding unit syntax of the         CLVS. Otherwise (sps_affine_enabled_flag is equal to 1), affine         model based motion compensation can be used in the CLVS.     -   sps_affine_type_flag specifies whether 6-parameter affine model         based motion compensation can be used for inter prediction. If         sps_affine_type_flag is equal to 0, the syntax shall be         constrained such that no 6-parameter affine model based motion         compensation is used in the CLVS, and cu_affine_type_flag is not         present in coding unit syntax in the CLVS. Otherwise         (sps_affine_type_flag is equal to 1), 6-parameter affine model         based motion compensation can be used in the CLVS. When not         present, the value of sps_affine_type_flag is inferred to be         equal to 0.     -   sps_affine_amvr_enabled_flag equal to 1 specifies that adaptive         motion vector difference resolution is used in motion vector         coding of affine inter mode. sps_affine_amvr_enabled_flag equal         to 0 specifies that adaptive motion vector difference resolution         is not used in motion vector coding of affine inter mode.     -   sps_affine_prof_enahled_flag specifies whether the prediction         refinement with optical flow can be used for affine motion         compensation. If sps_affine_prof_enabled_flag is equal to 0, the         affine motion compensation shall not be refined with optical         flow. Otherwise (sps_affine_prof_enabled_flag is equal to 1),         the affine motion compensation can be refined with optical flow.         When not present, the value of sps_affine_prof_enabled_flag is         inferred to be equal to 0.     -   sps_prof_pic_present_flag equal to 1 specifies that         pic_disable_prof_flag is present in PHs referring to the SPS.         sps_prof_pic_present_flag equal to 0 specifies that         pic_disable_prof_flag is not present in PHs referring to the         SPS. When sps_prof_pic_present_flag is not present, the value of         sps_prof_pic_present_flag is inferred to be equal to 0.     -   sps_palette_enabled_flag equal to 1 specifies that         pred_mode_plt_flag may be present in the coding unit syntax.         sps_palette_enabled_flag equal to 0 specifies that         pred_mode_plt_flag is not present in the coding unit syntax.         When sps_palette_enabled_flag is not present, it is inferred to         be equal to 0.     -   sps_act_enabled_flag specifies that whether adaptive colour         transform is enabled. If sps_act_enabled_flag is equal to 1,         adaptive colour transform may be used and the flag         cu_act_enabled_flag may be present in the coding unit syntax. If         sps_act_enabled_flag is equal to 0, adaptive colour transform is         not used and cu_act_enabled_flag is not present in the coding         unit syntax When sps_act_enabled_flag is not present, it is         inferred to be equal to 0.     -   sps_bcw_enabled_flag specifies whether bi-prediction with CU         weights can be used for inter prediction. If         sps_bcw_enabled_flag is equal to 0, the syntax shall be         constrained such that no bi-prediction with CU weights is used         in the CLVS, and bcw_idx is not present in coding unit syntax of         the CLVS. Otherwise (sps_bcw_enabled_flag is equal to 1),         bi-prediction with CU weights can be used in the CLVS.     -   sps_ibc_enabled_flag equal to 1 specifies that the IBC         prediction mode may be used in decoding of pictures in the CLVS.         sps_ibc_enabled_flag equal to 0 specifies that the IBC         prediction mode is not used in the CLVS. When         sps_ibc_enabled_flag is not present, it is inferred to be equal         to 0.     -   sps_ciip_enabled_flag specifies that ciip_flag may be present in         the coding unit syntax for inter coding units.         sps_ciip_enabled_flag equal to 0 specifies that ciip_flag is not         present in the coding unit syntax for inter coding units.     -   sps_fpel_mmvd_enabled_flag equal to 1 specifies that merge mode         with motion vector difference is using integer sample precision.         sps_fpel_mmvd_enabled_flag equal to 0 specifies that merge mode         with motion vector difference can use fractional sample         precision.     -   sps_triangle_enabled_flag specifies whether triangular shape         based motion compensation can be used for inter prediction.         sps_triangle_enabled_flag equal to 0 specifies that the syntax         shall be constrained such that no triangular shape based motion         compensation is used in the CLVS, and merge_triangle_split_dir,         merge_triangle_idx0, and merge_triangle_idx1 are not present in         coding unit syntax of the CLVS. sps_triangle_enabled_flag equal         to 1 specifies that triangular shape based motion compensation         can be used in the CLVS.     -   sps_lmcs_enabled_flag equal to 1 specifies that luma mapping         with chroma scaling is used in the CLVS. sps_lmcs_enabled_flag         equal to 0 specifies that luma mapping with chroma scaling is         not used in the CLVS.     -   sps_lfnst_enabled_flag equal to 1 specifies that lfnst_idx may         be present in intra coding unit syntax. sps_lfnst_enabled_flag         equal to 0 specifies that lfnst_idx is not present in intra         coding unit syntax.     -   sps_ladf_enabled_flag equal to 1, specifies that         sps_num_ladf_intervals_minus2,         sps_ladf_loweset_interval_qp_offset, sps_ladf_qp_offset[i], and         sps_ladf_delta_threshold_minus1[i] are present in the SPS.     -   sps_num_ladf_intervals_minus2 plus 1 specifies the number of         sps_ladf_delta_threshold_minus1[i] and sps_ladf_qp_offset[i]         syntax elements that are present in the SPS. The value of         sps_num_ladf_intervals_minus2 shall be in the range of 0 to 3,         inclusive.     -   sps_ladf_lowest_interval_qp_offset specifies the offset used to         derive the variable qP as specified. The value of         sps_ladf_lowest_interval_qp_offset shall be in the range of 0 to         63, inclusive.     -   sps_ladf_qp_offset[i] specifies the offset array used to derive         the variable qP as specified. The value of sps_ladf_qp_offset[i]         shall be in the range of 0 to 63, inclusive.     -   sps_ladf_delta_threshold_minus1[i] is used to compute the values         of SpsLadfIntervalLowerBound[i], which specifies the lower bound         of the i-th luma intensity level interval. The value of         sps_ladf_delta_threshold_minus1[i] shall be in the range of 0 to         2^(BitDepth)−3, inclusive.     -   The value of SpaLadfIntervalLowerBound[0] is set equal to 0.     -   For each value of i in the range of 0 to         sps_num_ladf_intervals_minus2, inclusive, the variable         SpsLadfIntervalLowerBound[i+1] is derived as follows:

SpsLadfIntervalLowerBound[i+1]=SpsLadfIntervalLowerBound[i]+sps_ladf_delta_threshold_minus1[i]+1

-   -   sps_scaling_list_enabled_flag equal to 1 specifies that a         scaling list is used for the scaling process for transform         coefficients. sps_scaling_list_enabled_flag equal to 0 specifies         that scaling list is not used for the scaling process for         transform coefficients.     -   sps_loop_filter_across_vitural_boundaries_disabled_presetnt_flag         equal to 1 specifies that the in-loop filtering operations are         disabled across the virtual boundaries in pictures referring to         the SPS.         sps_loop_filter_across_virtual_boundaries_disabled_present_flag         equal to 0 specifies that no such disabling of in-loop filtering         operations is applied in pictures referring to the SPS. In-loop         filtering operations include the deblocking filter, sample         adaptive offset filter, and adaptive loop filter operations.     -   sps_num_ver_virtual_boundaries specifies the number of         sps_virtual_boundaries_pos_x[i] syntax elements that are present         in the SPS. When sps_num_ver_virtual_boundaries is not present,         it is inferred to be equal to 0.     -   sps_virtual_boundaries_pos_x[i] is used to compute the value of         VirtualBoundariesPosX[i], which specifies the location of the         i-th vertical virtual boundary in units of luma samples.         sps_virtual_boundaries_pos_x[i] shall be in the range of 1 to         Ceil(pic_width_in_luma_samples+8)−1, inclusive.     -   sps_num_hor_virtual_boundaries specifies the number of         sps_virtual_boundaries_pos_y[i] syntax elements that are present         in the SPS. When sps_num_hor_virtual_boundaries is not present,         it is inferred to be equal to 0.     -   sps_vitrual_boundaries_pos_y[i] is used to compute the value of         VirtualBoundariesPosY[i], which specifies the location of the         i-th horizontal virtual boundary in units of luma samples.         sps_virtual_boundaries_pos_y[i] shall be in the range of 1 to         Ceil(pic_height_in_luma_samples+8)−1, inclusive.     -   sps_general_hrd_param_present_flag equal to 1 specifies that the         syntax structure general_hrd_parameters( ) is present in the SPS         RBSP syntax structure. sps_general_hrd_params_present_flag equal         to 0 specifies that the syntax structure general_hrd_parameters(         ) is not present in the SPS RBSP syntax structure.     -   sps_sub_layer_cpb_params_present_flag equal to 1 specifies that         the syntax structure old_hrd_parameters( ) in the SPS RBSP         includes HRD parameters for sub-layer representations with         TemporalId in the range of 0 to sps_max_sub_layers_minus1,         inclusive. sps_sub_layer_cpb_params_present_flag equal to 0         specifies that the syntax structure ols_hrd_parameters( ) in the         SPS RBSP includes HRD parameters for the sub-layer         representation with TemporalId equal to         sps_max_sub_layers_minus1 only. When sps_max_sub_layers_minus1         is equal to 0, the value of         sps_sub_layer_cpb_params_present_flag is inferred to be equal to         0.     -   When sps_sub_layer_cpb_params_present_flag is equal to 0, the         HRD parameters for the sub-layer representations with TemporalId         in the range of 0 to sps_max_sub_layers_minus1−1, inclusive, are         inferred to be the same as that for the sub-layer representation         with TemporalId equal to sps_max_sub_layers_minus1. These         include the HRD parameters starting from the         fixed_pic_rate_general_flag[i] syntax element till the         sub_layer_hrd_parameters(i) syntax structure immediately under         the condition “if (general_vcl_hrd_params_present_flag)” in the         ols_hrd_parameters syntax structure.     -   vui_parameters_present_flag equal to 1 specifies that the syntax         structure vui_parameters( ) is present in the SPS RBSP syntax         structure. vui_parameters_present_flag equal to 0 specifies that         the syntax structure vui_parameters( ) is not present in the SPS         RBSP syntax structure.     -   sps_extension_flag equal to 0 specifies that no         sps_extension_data_flag syntax elements are present in the SPS         RBSP syntax structure. sps_extension_flag equal to 1 specifies         that there are sps_extension_data_flag syntax elements present         in the SPS RBSP syntax structure.     -   sps_extension_data_flag may have any value. Its presence and         value do not affect decoder conformance to profiles specified in         this version of this Specification. Decoders conforming to this         version of this Specification shall ignore all         sps_extension_data_flag syntax elements.     -   As provided in Table 2, a NAL unit may include a picture         parameter set syntax structure. Table 4 illustrates the syntax         of the picture parameter set syntax structure provided in         JVET-P2001.

TABLE 4 Descriptor pic_parameter_set_rbsp( ) {  pps_pic_parameter_set_id ue(v)  pps_seq_parameter_set_id u(4)  pps_seq_parameter_set_id ue(v)  pic_width_in_luma_samples ue(v)  pic_height_in_luma_samples ue(v)  conformance_window_flag u(1)  if( conformance_window_flag ) {   conf_win_left_offset ue(v)   conf_win_right_offset ue(v)   conf_win_top_offset ue(v)   conf_win_bottom_offset ue(v)  }  scaling_window_flag u(1)  if( scaling_window_flag ) {   scaling_win_left_offset ue(v)   scaling_win_right_offset ue(v)   scaling_win_top_offset ue(v)   scaling_win_bottom_offset ue(v)  }  output_flag_present_flag u(1)  mixed_nalu_types_in_pic_flag u(1)  pps_subpic_id_signalling_present_flag u(1)  if( pps_subpics_id_signalling_present_flag ) {   pps_num_subpics_minus1 ue(v)   pps_subpic_id_len_minus1 ue(v)   for( i = 0; i <= pps_num_subpic_minus1; i++ )    pps_subpic_id[ i ] u(v)  }  no_pic_partition_flag u(1)  if( !no_pic_partition_flag ) {   pps_log2_ctu_size_minus5 u(2)   num_exp_tile_columns_minus1 ue(v)   num_exp_tile_rows_minus1 ue(v)   for( i = 0; i <= num_exp_tile_columns_minus1; i++ )    tile_column_width_minus1[ i ] ue(v)   for( i = 0; i <= num_exp_tile_rows_minus1; i++ )    tile_row_height_minus1[ i ] ue(v)   rect_slice_flag u(1)   if( rect_slice_flag )    single_slice_per_subpic_flag u(1)   if( rect_slice_flag && !single_slice_per_subpic_flag ) {    num_slices_in_pic_minus1 ue(v)    tile_idx_delta_present_flag u(1)    for( i = 0; i < num_slices_in_pic_minus1; i++ ) {     slice_width_in_tiles_minus1[ i ] ue(v)     slice_height_in_tiles_minus1[ i ] ue(v)     if( slice_width_in_tiles_minus1[ i ] = = 0 &&        slice_height_in_tiles_minus1[ i ] = = 0 ) {      num_slices_in_tile_minus1[ i ] ue(v)      numSlicesInTileMinus1 = num_slices_in_tile_minus1[ i ]      for( j = 0; j < numSlicesInTileMinus1; j++ )       slice_height_in_ctu_minus1[ i++ ] ue(v)     }     if( tile_idx_delta_present_flag && i < num_slices_in_pic_minus1 )      tile_idx_delta[ i ] se(v)    }   }   loop_filter_across_tiles_enabled_flag u(1)   loop_filter_across_slices_enabled_flag u(1)  }  entropy_coding_sync_enabled_flag u(1)  if( !no_pic_partition_flag || entropy_coding_sync_enabled_flag )   entry_point_offsets_present_flag u(1)  cabac_init_present_flag u(1)  for( i = 0; i < 2; i++ )   num_ref_idx_default_active_minus1[ i ] ue(v)  rpl1_idx_present_flag u(1)  init_qp_minus26 se(v)  if( sps_transform_skip_enabled_flag )   log2_transform_skip_max_size_minus2 ue(v)  cu_qp_delta_enabled_flag u(1)  pps_cb_qp_offset se(v)  pps_cr_qp_offset se(v)  pps_joint_cbcr_qp_offset_present_flag u(1)  if( pps_joint_cbcr_qp_offset_present_flag )   pps_joint_cbcr_qp_offset_value se(v)  pps_slice_chroma_qp_offsets_present_flag u(1)  cu_chroma_qp_offset_enabled_flag u(1)  if( cu_chroma_qp_offset_enabled_flag ) {   chroma_qp_offset_list_len_minus1 ue(v)   for( i = 0; i <= chroma_qp_offset_list_len_minus1; i++ ) {    cb_qp_offset_list[ i ] se(v)    cr_qp_offset_list[ i ] se(v)    if( pps_joint_cbcr_qp_offset_present_flag )     joint_cbcr_qp_offset_list[ i ] se(v)   }  }  pps_weighted_pred_flag u(1)  pps_weighted_bipred_flag u(1)  deblocking_filter_control_present_flag u(1)  if( deblocking_filter_control_present_flag ) {   deblocking_filter_override_enabled_flag u(1)   pps_deblocking_filter_disabled_flag u(1)   if( !pps_deblocking_filter_disabled_flag ) {    pps_beta_offset_div2 se(v)    pps_tc_offset_div2 se(v)   }  }  constant_slice_header_params_enabled_flag u(1)  if( constant_slice_header_params_enabled_flag ) {   pps_dep_quant_enabled_idc u(2)   for( i = 0; i < 2; i++ )    pps_ref_pic_list_sps_idc[ i ] u(2)   pps_mvd_l1_zero_idc u(2)   pps_collocated_from_l0_idc u(2)   pps_six_minus_max_num_merge_cand_plus1 ue(v)   pps_max_num_merge_cand_minus_max_num_triangle_cand_plus1 ue(v)  }  picture_header_extension_present_flag u(1)  slice_header_extension_present_flag u(1)  pps_extension_flag u(1)  if( pps_extension_flag )   while( more_rbsp_data( ) )    pps_extension_data_flag u(1)  rbsp_trailing_bits( ) }

-   -   With respect to Table 4, JVET-P2001 provides the following         semantics:     -   A PPS RBSP shall be available to the decoding process prior to         it being referenced, included in at least one AU with TemporalId         less than or equal to the TemporalId of the PPS NAL unit or         provided through external means.     -   All PPS NAL units with a particular value of         pps_pic_parameter_set_id within a PU shall have the same         content.     -   pps_pic_parameter_set_id identifies the PPS for reference by         other syntax elements. The value of pps_pic_parameter_set_id         shall be in the range of 0 to 63, inclusive.     -   PPS NAL units, regardless of the nuh_layer_id values, share the         same value space of pps_pic_parameter_set_id.     -   pps_seq_parameter_set_id specifies the value of         sps_seq_parameter_set_id for the SPS. The value of         pps_seq_parameter_set_id shall be in the range of 0 to 15,         inclusive. The value of pps_seq_parameter_set_id shall be the         same in all PPSs that are referred to by coded pictures in a         CLVS.     -   pic_width_in_luma_samples specifies the width of each decoded         picture referring to the PPS in units of luma samples.         pic_width_in_luma_samples shall not be equal to 0, shall be an         integer multiple of Max(8, MinCbSizeY), and shall be less than         or equal to pic_width_max_in_luma_samples.     -   When subpics_present_flag is equal to 1 or         ref_pic_resampling_enabled_flag equal to 0, the value of         pic_width_in_luma_samples shall be equal to         pic_width_max_in_luma_samples.     -   pic_height_in_luma_samples specifies the height of each decoded         picture referring to the PPS in units of luma samples.         Pic_height_in_luma_samples shall not be equal to 0 and shall be         an integer multiple of Max(8, MinCbSizeY), and shall be less         than or equal to pic_height_max_in_luma_samples.     -   When subpics_present_flag is equal to 1 or         ref_pic_resampling_enabled_flag equal to 0, the value of         pic_height_in_luma_samples shall be equal to         pic_height_max_in_luma_samples.     -   Let refPicWidthInLumaSamples and refPicHeightInLumaSamples be         the pic_width_in_luma_samples and pic_height_in_luma_samples,         respectively, of a reference picture of a current picture         referring to this PPS. Is a requirement of bitstream conformance         that all of the following conditions are satisfied:         -   pic_width_in_luma_samples*2 shall be greater than or equal             to refPicWidthInLumaSamples.         -   pic_height_in_luma_samples*2 shall be greater than or equal             to refPicHeightInLumaSamples.         -   pic_width_in_luma_samples shall be less than or equal to             refPicWidthInLumaSamples*8.         -   pic_height_in_luma_samples shall be less than or equal to             refPicHeightInLumaSamples*8.     -   The variables PicWidthInCtbsY, PicHeightInCtbsY, PicSizeInCtbaY,         PicWidthInMinCbsY, PicHeightInMinCbsY, PicSizeInMinCbsY,         PicSizeInSamplesY, PicWidthInSamplesC and PicHeightInSamplesC         are derived as follows:

PicWidthInCtbsY=Ceil(pic_width_in_luma_samples÷CtbSizeY)

PicHeightInCtbsY=Ceil(pic_height_in_luma_samples÷CtbSizeY)

PicSizeInCtbsY=PicWidthInCtbsY*PicHeightInCtbsY

PicWidthInMinCbsY=pic_width_in_luma_samples/MinCbSizeY

PicHeightInMinCbsY=pic_height_in_luma_samples/MinCbSizeY

PicSizeInMinCbsY=PicWidthInMinCbsY*PicHeightInMinCbsY

PicSizeInSamplesY=pic_width_in_luma_samples*pic_height_in_luma_samples

PicWidthInSamplesC=pic_width_in_luma_samples/SubWidthC

PicHeightInSamplesC=pic_height_in_luma_samples/SubHeightC

-   -   conformance_window_flag equal to 1 indicates that the         conformance cropping window offset parameters follow next in the         SPS. conformance_window_flag equal to 0 indicates that the         conformance cropping window offset parameters are not present.     -   conf_win_left_offset, conf_win_right_oiffset,         cont_win_top_offset, and conf_win_bottom_offset specify the         samples of the pictures in the CLVS that are output from the         decoding process, in terms of a rectangular region specified in         picture coordinates for output. When conformance_window_flag is         equal to 0, the values of conf_win_left_offset,         confwin_right_offset, conf_wintop_offset, and         conf_win_bottom_offset are inferred to be equal to 0.     -   The conformance cropping window contains the luma samples with         horizontal picture coordinates from         SubWidthC*conf_win_left_offset to         pic_width_in_luma_samples−(SubWidthC*conf_win_right_offset+1)         and vertical picture coordinates from         SubHeightC*conf_win_top_offset to         pic_height_in_luma_samples−(SubHeightC*conf_win_bottom_offset+1),         inclusive.     -   The value of         SubWidthC*(conf_win_left_offset+conf_win_right_offset) shall be         less than pic_width_in_lumas_samples, and the value of         SubHeightC*(conf_win_top_offset+conf_win_bottom_offset) shall be         less than pic_height_in_luma_samples.     -   When ChromaArrayType is not equal to 0, the corresponding         specified samples of the two chroma arrays are the samples         having picture coordinates (x/SubWidthC, y/SubHeightC), where         (x, y) are the picture coordinates of the specified luma         samples.         -   NOTE—The conformance cropping window offset parameters are             only applied at the output. All internal decoding processes             are applied to the uncropped picture size.     -   Let ppaA and ppsB be any two PPSs referring to the same SPS. It         is a requirement of bitstream conformance that, when ppaA and         ppsB have the same the values of pic_width_in_luma_samples and         pic_height_in_luma_samples, respectively, ppaA and ppsB shall         have the same values of conf_win_left_offset,         conf_win_right_offset, conf_win_top_offset, and         conf_win_bottom_offset, respectively.     -   scaling_window_flag equal to 1 specifies that the scaling window         offset parameters are present in the PPS. scaling_window_flag         equal to 0 specifies that the scaling window offset parameters         are not present in the PPS. When ref_pic_resampling_enabled_flag         is equal to 0, the value of scaling_window_flag shall be equal         to 0.     -   scaling_win_left_offset, scaling_win_right_offset,         scaling_win_top_offset, and scaling_win_bottom_offset specify         the offsets, in units of luma samples, that are applied to the         picture size for scaling ratio calculation. When         scaling_window_flag is equal to 0, the values of         scaling_win_left_offset, scaling_win_right_offset,         scaling_win_top_offset, and scaling_win_bottom_offset are         inferred to be equal to 0.     -   The value of         SubWidthC*(scaling_win_left_offset+scaling_win_right_offset)         shall be less than pic_width_in_luma_samples, and the value of         SubHeightC*(scaling_win_top_offset+scaling_win_bottom_offset)         shall be less than pic_height_in_luma_samples.     -   The variables PicOutputWidthL and PicOutputHeightL are derived         as follows:

PicOutputWidthL=pic_width_in_luma_samples−SubWidthC*(scaling_win_right_offset+scaling_win_left_offset)

PicOutputHeightL=pic_height_in_pic_size_units−

-   -   output_flag_present_flag equal to 1 indicates that the         pic_output_flag syntax element is present in slice headers         referring to the PPS. output_flag_present_flag equal to 0         indicates that the pic_output_flag syntax element is not present         in slice headers referring to the PPS.     -   mixed_nalu_types_in_pic_flag equal to 1 specifies that each         picture referring to the PPS has more than one VCL NAL unit and         that the VAL NAL units do not have the same value of         nal_unit_type and that the picture is not an IRAP picture.         mixed_nalu_types_in_pic_flag equal to 0 specifies that each         picture referring to the PPS has one or more VCL NAL units and         the VCL NAL units of each picture referring to the PPS have the         same value of nal_unit_type.     -   When no_mixed_nalu_types_in_pic_constraint_flag is equal to 1,         the value of mixed_nalu_types_in_pic_flag shall be equal to 0.     -   For each slice with a nal_unit_type value nalUnitTypeA in the         range of IDR_W_RADL to CRA_NUT, inclusive, in a picture picA         that also contains one or more slices with another value of         nal_unit_type (i.e., the value of mixed_nalu_types_in_pic_flag         for the picture picA is equal to 1), the following applies:         -   The slice shall belong to a subpicture subpicA for which the             value of the corresponding sub_pic_treated_as_pic_flag[i] is             equal to 1.         -   The slice shall not belong to a subpicture of picA             containing VCL NAL units with nal_unit_type not equal to             nalUnitTypeA.         -   For all the following PUs in the CLVS in decoding order,             neither RefPicList[0] nor RefPicList[1] of a slice in             subpicA shall include any picture preceding picA in decoding             order in an active entry.     -   pps_subpic_id_signalling_present_flag equal to 1 specifies that         subpicture ID mapping is signalled in the PPS.         pps_subpic_id_signalling_present_flag equal to 0 specifies that         subpicture ID mapping is not signalled in the PPS. When         sps_subpic_id_present_flag is 0 or         sps_subpic_id_signalling_present_flag is equal to 1,         pps_subpic_id_signalling_present_flag shall be equal to 0.     -   pps_num_subpics_minus1 plus 1 specifies the number of         subpictures in the coded pictures referring to the PPS.     -   It is a requirement of bitstream conformance that the value of         pps_num_subpic_minus1 shall be equal to sps_num_subpics_minus1.     -   pps_subpic_id_len_minus1 plus 1 specifies the number of bits         used to represent the syntax element pps_subpic_id[i]. The value         of pps_subpic_id_len_minus1 shall be in the range of 0 to 15,         inclusive.     -   It is a requirement of bitstream conformance that the value of         pps_subpic_id_len_minus1 shall be the same for all PPSs that are         referred to by coded pictures in a CLVS.     -   pps_subpic_id[i] specifies that subpicture ID of the i-th         subpicture. The length of the pps_subpic_id[i] syntax element is         pps_subpic_id_len_minus1+1 bits.     -   no_pic_partition_flag equal to 1 specifies that no picture         partitioning applied to each picture referring to the PPS.         no_pic_partition_flag equal to 0 specifies each picture         referring to the PPS may be partitioned into more than one tile         or slice.     -   It is a requirement of bitstream conformance that the value of         no_pic_partition_flag shall be the same for all PPSs that are         referred to by coded pictures within a CLVS.     -   It is a requirement of bitstream conformance that the value of         no_pic_partition_flag shall not be equal to 1 when the value of         sps_num_subpics_minus1+1 is greater than 1.     -   pps_log2_ctu_size_minus5 plus 5 specifies the luma coding tree         block size of each CTU. pps_log2_ctu_size_minus5 shall be equal         to sps_log2_ctu_size_minus5.     -   num_exp_tile_column_minus1 plus 1 specifies the number of         explicitly provided tile column widths. The value of         num_exp_tile_columns_minus1 shall be in the range of 0 to         PicWidthInCtbsY−1, inclusive. When no_pic_partition_flag is         equal to 1, the value of num_exp_tile_columns_minus1 is inferred         to be equal to 0.     -   num_exp_tile_rows_minus1 plus 1 specifies the number of         explicitly provided tile row heights. The value of         num_exp_tile_rows_minus1 shall be in the range of 0 to         PicHeightInCtbsY−1, inclusive. When no_pic_partition_flag is         equal to 1, the value of num_tile_rows_minus1 is inferred to be         equal to 0.     -   tile_column_width_minus1[i] plus 1 specifies the width of the         i-th tile column in units of CTBs for i in the range of 0 to         num_exp_tile_columns_minus1−1, inclusive.         tile_column_width_minus1[num_exp_tile_columns_minus1] is used to         derive the width of the tile columns with index greater than or         equal to num_exp_tile_columns_minus1 as specified. When not         present, the value of tile_column_width_minus1[0] is inferred to         be equal to PicWidthInCtbsY−1.     -   tile_row_height_minus1[i] plus 1 specifies the height of the         i-th tile row in unite of CTBs for i in the range of 0 to         num_exp_tile_rows_minus1−1, inclusive.         tile_row_height_minus1[num_exp_tile_rows_minus1] is used to         derive the height of the tile rows with index greater than or         equal to num_exp_tile_rows_minus1 as specified. When not         present, the value of tile_row_height_minus1[0] is inferred to         be equal to PicHeightInCtbsY−1.     -   rect_slice_flag equal to 0 specifies that tiles within each         slice are in raster scan order and the slice information is not         signalled in PPS. rect_slice_flag equal to 1 specifies that         tiles within each slice cover a rectangular region of the         picture and the slice information is signalled in the PPS. When         not present, rect_slice_flag is inferred to be equal to 1.     -   single_slice_per_subpic_flag equal to 1 specifies that each         subpicture consists of one and only one rectangular slice.         single_slice_per_subpic_flag equal to 0 specifies that each         subpicture may consist one or more rectangular slices. When         subpics_present_flag is equal to 0, single_slice_per_subpic_flag         shall be equal to 0. When single_slice_per_subpic_flag is equal         to 1, num_slices_in_pic_minus1 is inferred to be equal to         sps_num_subpics_minus1.     -   num_slices_in_pic_minus1 plus 1 specifies the number of         rectangular slices in each picture referring to the PPS. The         value of num_slices_in_pic_minus1 shall be in the range of 0 to         MaxSlicesPerPicture−1, inclusive, where MaxSlicesPerPicture is         specified in Annex A. When no_pic_partition_flag is equal to 1,         the value of num_slices_in_pic_minus1 is inferred to be equal to         0.     -   tile_idx_delta_present_flag equal to 0 specifies that         tile_idx_delta values are not present in the PPS and that all         rectangular slices in pictures referring to the PPS are         specified in raster order according to a process defined.         tile_idx_delta_present_flag equal to 1 specifies that         tile_idx_delta values may be present in the PPS and that all         rectangular slices in pictures referring to the PPS are         specified in the order indicated by the values of         tile_idx_delta.     -   slice_width_in_tiles_minus1[i] plus 1 specifies the width of the         i-th rectangular slice in units of tile columns. The value of         slice_width_in_tiles_minus1[i] shall be in the range of 0 to         NumTileColumns−1, inclusive. When not present, the value of         slice_width_in_tiles_minus1[i] is inferred as specified.     -   slice_height_in_tiles_minus1[i] plus 1 specifies the height of         the i-th rectangular slice in units of tile rows. The value of         slice_height_in_tiles_minus1[i] shall be in the range of 0 to         NumTileRows−1, inclusive. When not present, the value of         slice_height_in_tiles_minus1[i] is inferred as specified.     -   num_slices_in_tile_minus1[i] plus 1 specifies the number of         slices in the current tile for the case where the i-th slice         contains a subset of CTU rows from a single tile. The value of         num_slices_in_tile_minus1[i] shall be in the range of 0 to         RowHeight[tileY]−1, inclusive, where tileY is the tile row index         containing the i-th slice. When not present, the value of         num_slices_in_tile_minus1[i] is inferred to be equal to 0.     -   slice_height_in_ctu_minus1[i] plus 1 specifies the height of the         i-th rectangular slice in units of CTU rows for the case where         the i-th slice contains a subset of CTU rows from a single tile.         The value of slice_height_in_ctu_minus1[i] shall be in the range         of 0 to RowHeight[tileY]−1, inclusive, where tileY is the tile         row index containing the i-th slice.     -   tile_idx_delta[i] specifies the difference in tile index between         the i-th rectangular slice and the (i+1)-th rectangular slice.         The value of tile_idx_delta[i] shall be in the range of         −NumTilesInPic+1 to NumTilesInPic−1, inclusive. When not         present, the value of tile_idx_delta[i] is inferred to be equal         to 0. In all other cases, the value of tile_idx_delta[i] shall         not be equal to 0.     -   loop_filter_across_tiles_enabled_flag equal to 1 specifies that         in-loop filtering operations may be performed across tile         boundaries in pictures referring to the PPS.         loop_filter_across_tiles_enabled_flag equal to 0 specifies that         in-loop filtering operations are not performed across tile         boundaries in pictures referring to the PPS. The in-loop         filtering operations include the deblocking filter, sample         adaptive offset filter, and adaptive loop filter operations.         When not present, the value of         loop_filter_across_tiles_enabled_flag is inferred to be equal to         1.     -   loop_filter_across_slices_enabled_flag equal to 1 specifies that         in-loop filtering operations may be performed across slice         boundaries in pictures referring to the PPS.         loop_filter_across_slice_enabled_flag equal to 0 specifies that         in-loop filtering operations are not performed across slice         boundaries in pictures referring to the PPS. The in-loop         filtering operations include the deblocking filter, sample         adaptive offset filter, and adaptive loop filter operations.         When not present, the value of         loop_filter_across_slices_enabled_flag is inferred to be equal         to 0.     -   entropy_coding_sync_enabled_flag equal to 1 specifies that a         specific synchronization process for context variables is         invoked before decoding the CTU that includes the first CTB of a         row of CTBs in each tile in each picture referring to the PPS,         and a specific storage process for context variables is invoked         after decoding the CTU that includes the first CTB of a row of         CTBs in each tile in each picture referring to the PPS.         entropy_coding_sync_enabled_flag equal to 0 specifies that no         specific synchronization process for context variables is         required to be invoked before decoding the CTU that includes the         first CTB of a row of CTBs in each tile in each picture         referring to the PPS, and no specific storage process for         context variables is required to be invoked after decoding the         CTU that includes the first CTB of a row of CTBs in each tile in         each picture referring to the PPS.     -   It is a requirement of bitstream conformance that the value of         entropy_coding_sync_enabled_flag shall be the same for all PPSs         that are referred to by coded pictures within a CLVS.     -   cabac_init_present_flag equal to 1 specifies that         cabac_init_flag is present in slice headers referring to the         PPS. cabac_init_present_flag equal to 0 specifies that         cabac_init_flag is not present in slice headers referring to the         PPS.     -   num_ref_idx_default_active_minus1[i] plus 1, when i is equal to         0, specifies the inferred value of the variable         NumRefIdxActive[0] for P or B slices with         num_ref_idx_active_override_flag equal to 0, and, when i is         equal to 1, specifies the inferred value of NumRefIdxActive[1]         for B slices with num_ref_idx_active_override_flag equal to 0.         The value of num_ref_idx_default_active_minus1[i] shall be in         the range of 0 to 14, inclusive.     -   rpl1_idx_present_flag equal to 0 specifies that         ref_pic_list_sps_flag[1] and ref_pic_list_idx[1] are not present         in slice headers. rpl1_idx_present_flag equal to 1 specifies         that ref_pic_list_sps_flag[1] and ref_pic_list_idx[1] may be         present in slice headers.     -   init_gp_minus26 plus 26 specifies the initial value of         SliceQp_(Y) for each slice referring to the PPS. The initial         value of SliceQp_(Y) is modified at the slice layer when a         non-zero value of slice_qp_delta is decoded. The value of         init_qp_minus26 shall be in the range of −(26+QpBdOffset) to         +37, inclusive.     -   log2_transform_skip_max_size_minus2 specifies the maximum block         size used for transform skip, and shall be in the range of 0 to         3.     -   When not present, the value of         log2_transform_skip_max_size_minus2 is inferred to be equal to         0.     -   The variable MaxTSize is set equal to         1<<(log2_transform_skip_max_size_minus2+2).     -   cu_qp_delta_enabled_flag equal to 1 specifies that the         pic_cu_qp_delta_subdiv_intra_slice and         pic_cu_qp_delta_subdiv_inter_slice syntax elements are present         in PHs referring to the PPS and that cu_qp_delta_abs may be         present in the transform unit syntax. cu_qp_delta_enabled_flag         equal to 0 specifies that the pic_cu_qp_delta_subdiv_intra_slice         and pic_cu_qp_delta_subdiv_inter_slice syntax elements are not         present in PHs referring to the PPS and that cu_qp_delta_abs is         not present in the transform unit syntax.     -   pps_cb_qp_offset and pps_cr_qp_offset specify the offsets to the         luma quantization parameter Qp′_(Y) used for deriving Qp′_(Cb)         and Qp′_(Cr), respectively. The values of pps_cb_qp_offset and         pps_cr_qp_offset shall be in the range of −12 to +12, inclusive.         When ChromaArrayType is equal to 0, pps_cb_qp_offset and         pps_cr_qp_offset are not used in the decoding process and         decoders shall ignore their value.     -   pps_joint_cbcr_qp_offset_present_flag equal to 1 specifies that         pps_joint_cbcr_qp_offset_value and joint_cbcr_qp_offset_list[i]         are present in the PPS RBSP syntax structure.         pps_joint_cbcr_qp_offset_present_flag equal to 0 specifies that         pps_joint_cbcr_qp_offset_value and joint_cbcr_qp_offset_list[i]         are not present in the PPS RBSP syntax structure. When         ChromaArrayType is equal to 0 or sps_joint_cbcr_enabled_flag is         equal to 0, the value of pps_joint_cbcr_qp_offset_present_flag         shall be equal to 0.     -   pps_joint_cbcr_qp_offfet_value specifies the offset to the luma         quantization parameter Qp′_(Y) used for deriving Qp′_(CbCr). The         value of pps_joint_cbcr_qp_offset_value shall be in the range of         −12 to +12, inclusive. When ChromaArrayType is equal to 0 or         sps_joint_cbcr_enabled_flag is equal to 0,         pps_joint_cbcr_qp_offset_value is not used in the decoding         process and decoders shall ignore its value. When         pps_joint_cbcr_gp_offset_present_flag is equal to 0,         pps_joint_cbcr_qp_offset_value is not present and is inferred to         be equal to 0.     -   pps_slice_chroma_qp_offsets_present_flag equal to 1 indicates         that the slice_cb_qp_offset and slice_cr_qp_offset syntax         elements are present in the associated slice headers.         pps_slice_chroma_qp_offsets_present_flag equal to 0 indicates         that these syntax elements are not present in the associated         slice headers. When ChromaArrayType is equal to 0,         pps_slice_chroma_qp_offsets_present_flag shall be equal to 0.     -   cu_chroma_qp_offset_enabled_flag equal to 1 specifies that the         pic_cu_chroma_qp_offset_flag_intra_slice and         pic_cu_chroma_qp_offset_flag_inter_slice may be present in the         transform unit syntax. cu_chroma_qp_offset_enabled_flag equal to         0 specifies that the pic_cu_chroma_qp_offset_flag_intra_slice         and pic_cu_chroma_qp_offset_flag_inter_slice are not present in         the transform unit syntax. When ChromaArrayType is equal to 0,         it is a requirement of bitstream conformance that the value of         cu_chroma_qp_offset_enabled_flag shall be equal to 0.     -   chroma_qp_offset_list_len_minus1 plus 1 specifies the number of         cb_qp_offset_list[i], cr_qp_offset_list[i], and         joint_cbcr_qp_offset_list[i], syntax elements that are present         in the PPS. The value of chroma_qp_offset_list_len_minus1 shall         be in the range of 0 to 5, inclusive.     -   cb_qp_offset_list[i], cr_qp_offset_list[i], and         joint_cbcr_qp_offset_list[i], specify offsets used in the         derivation of Qp′_(Cb), Qp′_(Cr), and Qp′_(CbCr), respectively.         The values of cb_qp_offset_list[i], cr_qp_offset_list[i], and         joint_cbcr_qp_offset_list[i] shall be in the range of −12 to         +12, inclusive. When pps_joint_cbcr_qp_offset_present_flag is         equal to 0, joint_cbcr_qp_offset_list[i] is not present and it         is inferred to be equal to 0.     -   pps_weighted_pred_flag equal to 0 specifies that weighted         prediction is not applied to P slices referring to the PPS.         pps_weighted_pred_flag equal to 1 specifies that weighted         prediction is applied to P slices referring to the PPS. When         sps_weighted_pred_flag is equal to 0, the value of         pps_weighted_pred_flag shall be equal to 0.     -   pps_weighted_bipred_flag equal to 0 specifies that explicit         weighted prediction is not applied to B slices referring to the         PPS. pps_weighted_bipred_flag equal to 1 specifies that explicit         weighted prediction is applied to B slices referring to the PPS.         When sps_weighted_bipred_flag is equal to 0, the value of         pps_weighted_bipred_flag shall be equal to 0.     -   deblocking_filter_control_present_flag equal to 1 specifies the         presence of deblocking filter control syntax elements in the         PPS. deblocking_filter_control_present_flag equal to 0 specifies         the absence of deblocking filter control syntax elements in the         PPS.     -   deblocking_filter_override_enabled_flag equal to 1 specifies the         presence of pic_deblocking_filter_override_flag in the PHs         referring to the PPS or slice_deblocking_filter_override_flag in         the slice headers referring to the PPS.         deblocking_filter_override_enabled_flag equal to 0 specifies the         absence of pic_deblocking_filter_override_flag in PHs referring         to the PPS or slice_deblocking_filter_override_flag in slice         headers referring to the PPS. When not present, the value of         deblocking_filter_override_enabled_flag is inferred to be equal         to 0.     -   pps_deblocking_filter_disabled_flag equal to 1 specifies that         the operation of deblocking filter is not applied for slices         referring to the PPS in which         slice_deblocking_filter_disabled_flag is not present.         pps_deblocking_filter_disabled_flag equal to 0 specifies that         the operation of the deblocking filter is applied for slices         referring to the PPS in which         slice_deblocking_filter_disabled_flag is not present. When not         present, the value of pps_deblocking_filter_disabled_flag is         inferred to be equal to 0.     -   pps_beta_offset_div2 and pps_tc_offset_div2 specify the default         deblocking parameter offsets for ß and tC (divided by 2) that         are applied for slices referring to the PPS, unless the default         deblocking parameter offsets are overridden by the deblocking         parameter offsets present in the slice headers of the slices         referring to the PPS. The values of pps_beta_offset_div2 and         pps_tc_offset_div2 shall both be in the range of −6 to 6,         inclusive. When not present, the value of pps_beta_offset_div2         and pps_tc_offset_div2 are inferred to be equal to 0.     -   constant_slice_header_params_enabled_flag equal to 0 specifies         that pps_dep_quant_enabled_idc, pps_ref_pic_list_sps_idc[i],         pps_mvd_l1_zero_idc, pps_collocated_from_l0_idc,         pps_six_minus_max_num_merge_cand_plus1, and         pps_max_num_merge_cand_minus_max_num_triangle_cand_plus1 are         inferred to be equal to 0.         constant_slice_header_params_enabled_flag equal to 1 specifies         that these syntax elements are present in the PPS.     -   pps_dep_quant_enabled_idc equal to 0 specifies that the syntax         element pic_dep_quant_enabled_flag is present in PHs referring         to the PPS. pps_dep_quant_enabled_idc equal to 1 or 2 specifies         that the syntax element pic_dep_quant_enabled_flag is not         present in PHs referring to the PPS. pps_dep_quant_enabled_idc         equal to 3 is reserved for future use by ITU-T|ISO/IEC.     -   pps_ref_pic_list_sps_idc[i] equal to 0 specifies that the syntax         element pic_rpl_sps_flag[i] is present in PHs referring to the         PPS or slice_rpl_sps_flag[i] is present in slice header         referring to the PPS. pps_ref_pic_list_sps_idc[i] equal to 1 or         2 specifies that the syntax element pic_rpl_sps_flag[i] is not         present in PHs referring to the PPS and slice_rpl_sps_flag[i] is         not present in slice header referring to the PPS.         pps_ref_pic_list_sps_idc[i] equal to 3 is reserved for future         use by ITU-T|ISO/IEC.     -   pps_mvd_l1_zero_idc equal to 0 specifies that the syntax element         mvd_l1_zero_flag is present in PHs referring to the PPS.         pps_mvd_l1_zero_idc equal to 1 or 2 specifies that         mvd_l1_zero_flag is not present in PHs referring to the PPS.         pps_mvd_l1_zero_idc equal to 3 is reserved for future use by         ITU-T|ISO/IEC.     -   pps_collocated_from_l0_idc equal to 0 specifies that the syntax         element collocated_from_l0_flag is present in slice header of         slices referring to the PPS. pps_collocatedfrom_l0_idc equal to         1 or 2 specifies that the syntax element collocated_from_l0_flag         is not present in slice header of slices referring to the PPS.         pps_collocated_from_l0_idc equal to 3 is reserved for future use         by ITU-T|ISO/IEC.     -   pps_six_minus_max_num_merge_cand_plus1 equal to 0 specifies that         pic_six_minus_max_num_merge_cand is present in PHs referring to         the PPS. pps_six_minus_max_num_merge_cand_plus1 greater than 0         specifies that pic_six_minus_max_num_merge_cand is not present         in PHs referring to the PPS. The value of         pps_six_minus_max_num_merge_cand_plus1 shall be in the range of         0 to 6, inclusive.     -   pps_max_num_merge_cand_minus_num_triangle_cand_plus1 equal to 0         specifies that         pic_max_num_merge_cand_minus_max_num_triangle_cand is present in         PHs of slices referring to the PPS.         pps_max_num_merge_cand_minus_max_num_triangle_cand_plus1 greater         than 0 specifies that         pic_max_num_merge_cand_minus_max_num_triangle_cand is not         present in PHs referring to the PPS. The value of         pps_max_num_merge_cand_minus_max_num_triangle_cand_plus1 shall         be in the range of 0 to MaxNumMergeCand −1.     -   picture_header_extension_present_flag equal to 0 specifies that         no PH extension syntax elements are present in PHs referring to         the PPS. picture_header_extension_present_flag equal to 1         specifies that PH extension syntax elements are present in PHs         referring to the PPS. picture_header_extension_present_flag         shall be equal to 0 in bitstreams conforming to this version of         this Specification.     -   slice_header_extension_present_flag equal to 0 specifies that no         slice header extension syntax elements are present in the slice         headers for coded pictures referring to the PPS.         slice_header_extension_present_flag equal to 1 specifies that         slice header extension syntax elements are present in the slice         headers for coded pictures referring to the PPS.         slice_header_extension_present_flag shall be equal to 0 in         bitstreams conforming to this version of this Specification.     -   pps_extension_flag equal to 0 specifies that no         pps_extension_data_flag syntax elements are present in the PPS         RBSP syntax structure. pps_extension_flag equal to 1 specifies         that there are pps_extension_data_flag syntax elements present         in the PPS RBSP syntax structure.     -   pps_extension_data_flag may have any value. Its presence and         value do not affect decoder conformance to profiles specified in         this version of this Specification. Decoders conforming to this         version of this Specification shall ignore all         pps_extension_data_flag syntax elements.     -   As provided in Table 2, a NAL unit may include a picture header         syntax structure. Table 5 illustrates the syntax of the picture         header syntax structure provided in JVET-P2001.

TABLE 5 Descriptor picture_header_rbsp( ) {  non_reference_picture_flag u(1)  gdr_pic_flag u(1)  no_output_of_prior_pics_flag u(1)  if( gdr_pic_flag )   recovery_poc_cnt ue(v)  ph_pic_parameter_set_id ue(v)  if( sps_poc_msb_flag ) {   ph_poc_msb_present_flag u(1)   if( ph_poc_msb_present_flag )    poc_msb_val u(v)  }  if( sps_subpic_id_present_flag && !sps_subpic_id_signalling_flag ) {   ph_subpic_id_signalling_present_flag u(1)   if( ph_subpics_id_signalling_present_flag ) {    ph_subpic_id_len_minus1 ue(v)    for( i = 0; i <= sps_num_subpics_minus1; i++ )     ph_subpic_id[ i ] u(v)   }  }  if( !sps_loop_filter_across_virtual_boundaries_disabled_present_flag ) {   ph_loop_filter_across_virtual_boundaries_disabled_present_flag u(1)   if( ph_loop_filter_across_virtual_boundaries_disabled_present_flag ) {    ph_num_ver_virtual_boundaries u(2)    for( i = 0; i < ph_num_ver_virtual_boundaries; i++ )     ph_virtual_boundaries_pos_x[ i ] u(13)    ph_num_hor_virtual_boundaries u(2)    for( i = 0; i < ph_num_hor_virtual_boundaries; i++ )     ph_virtual_boundaries_pos_y[ i ] u(13)   }  }  if( separate_colour_plane_flag = = 1 )   colour_plane_id u(2)  if( output_flag_present_flag )   pic_output_flag u(1)  pic_rpl_present_flag u(1)  if( pic_rpl_present_flag ) {   for( i = 0; i < 2; i++ ) {    if( num_ref_pic_lists_in_sps[ i ] > 0 && !pps_ref_pic_list_sps_idc[ i ] &&       ( i = = 0 || ( i = = 1 && rpl1_idx_present_flag ) ) )     pic_rpl_sps_flag[ i ] u(1)    if( pic_rpl_sps_flag[ i ] ) {     if( num_ref_pic_lists_in_sps[ i ] > 1 &&        ( i = = 0 || ( i = = 1 && rpl1_idx_present_flag ) ) )      pic_rpl_idx[ i ] u(v)    } else     ref_pic_list_struct( i, num_ref_pic_lists_in_sps[ i ] )    for( j = 0; j < NumLtrpEntries[ i ][ RplsIdx[ i ] ]; j++ ) {     if( ltrp_in_slice_header_flag[ i ][ RplsIdx[ i ] ] )      pic_poc_lsb_lt[ i ][ j ] u(v)     pic_delta_poc_msb_present_flag[ i ][ j ] u(1)     if( pic_delta_poc_msb_present_flag[ i ][ j ] )      pic_delta_poc_msb_cycle_lt[ i ][ j ] ue(v)    }   }  }  if( partition_constraints_override_enabled_flag ) {   partition_constraints_override_flag ue(v)   if( partition_constraints_override_flag ) {    pic_log2_diff_min_qt_min_cb_intra_slice_luma ue(v)    pic_log2_diff_min_qt_min_cb_inter_slice ue(v)    pic_max_mtt_hierarchy_depth_inter_slice ue(v)    pic_max_mtt_hierarchy_depth_intra_slice_luma ue(v)    if( pic_max_mtt_hierarchy_depth_intra_slice_luma != 0 ) {     pic_log2_diff_max_bt_min_qt_intra_slice_luma ue(v)     pic_log2_diff_max_tt_min_qt_intra_slice_luma ue(v)    }    if( pic_max_mtt_hierarchy_depth_inter_slice != 0 ) {     pic_log2_diff_max_bt_min_qt_inter_slice ue(v)     pic_log2_diff_max_tt_min_qt_inter_slice ue(v)    }    if( qtbtt_dual_tree_intra_flag ) {     pic_log2_diff_min_qt_min_cb_intra_slice_chroma ue(v)     pic_max_mtt_hierarchy_depth_intra_slice_chroma ue(v)     if( pic_max_mtt_hierarchy_depth_intra_slice_chroma != 0 ) {      pic_log2_diff_max_bt_min_qt_intra_slice_chroma ue(v)      pic_log2_diff_max_tt_min_qt_intra_slice_chroma ue(v)     }    }   }  }  if( cu_qp_delta_enabled_flag ) {   pic_cu_qp_delta_subdiv_intra_slice ue(v)   pic_cu_qp_delta_subdiv_inter_slice ue(v)  }  if( cu_chroma_qp_offset_enabled_flag ) {   pic_cu_chroma_qp_offset_subdiv_intra_slice ue(v)   pic_cu_chroma_qp_offset_subdiv_inter_slice ue(v)  }  if( sps_temporal_mvp_enabled_flag )   pic_temporal_mvp_enabled_flag u(1)  if(!pps_mvd_l1_zero_idc )   mvd_l1_zero_flag u(1)  if( !pps_six_minus_max_num_merge_cand_plus1 )   pic_six_minus_max_num_merge_cand ue(v)  if( sps_affine_enabled_flag )   pic_five_minus_max_num_subblock_merge_cand ue(v)  if( sps_fpel_mmvd_enabled_flag )   pic_fpel_mmvd_enabled_flag u(1)  if( sps_bdof_pic_present_flag )   pic_disable_bdof_flag u(1)  if( sps_dmvr_pic_present_flag )   pic_disable_dmvr_flag u(1)  if( sps_prof_pic_present_flag )   pic_disable_prof_flag u(1)  if( sps_triangle_enabled_flag && MaxNumMergeCand >= 2 &&    !pps_max_num_merge_cand_minus_max_num_triangle_cand_minus1 )   pic_max_num_merge_cand_minus_max_num_triangle_cand ue(v)  if ( sps_ibc_enabled_flag )   pic_six_minus_max_num_ibc_merge_cand ue(v)  if( sps_joint_cbcr_enabled_flag )   pic_joint_cbcr_sign_flag u(1)  if( sps_sao_enabled_flag ) {   pic_sao_enabled_present_flag u(1)   if( pic_sao_enabled_present_flag ) {    pic_sao_luma_enabled_flag u(1)    if(ChromaArrayType != 0 )     pic_sao_chroma_enabled_flag u(1)   }  }  if( sps_alf_enabled_flag ) {   pic_alf_enabled_present_flag u(1)   if( pic_alf_enabled_present_flag ) {    pic_alf_enabled_flag u(1)    if( pic_alf_enabled_flag ) {     pic_num_alf_aps_ids_luma u(3)     for( i = 0; i < pic_num_alf_aps_ids_luma; i++ )      pic_alf_aps_id_luma[ i ] u(3)     if( ChromaArrayType != 0 )      pic_alf_chroma_idc u(2)     if( pic_alf_chroma_idc )      pic_alf_aps_id_chroma u(3)    }   }  }  if ( !pps_dep_quant_enabled_flag )   pic_dep_quant_enabled_flag u(1)  if( !pic_dep_quant_enabled_flag )   sign_data_hiding_enabled_flag u(1)  if( deblocking_filter_override_enabled_flag ) {   pic_deblocking_filter_override_present_flag u(1)   if( pic_deblocking_filter_override_present_flag ) {    pic_deblocking_filter_override_flag u(1)    if( pic_deblocking_filter_override_flag ) {     pic_deblocking_filter_disabled_flag u(1)     if( !pic_deblocking_filter_disabled_flag ) {      pic_beta_offset_div2 se(v)      pic_tc_offset_div2 se(v)     }    }   }  }  if( sps_lmcs_enabled_flag ) {   pic_lmcs_enabled_flag u(1)   if( pic_lmcs_enabled_flag ) {    pic_lmcs_aps_id u(2)    if( ChromaArrayType != 0 )     pic_chroma_residual_scale_flag u(1)   }  }  if( sps_scaling_list_enabled_flag ) {   pic_scaling_list_pic_present_flag u(1)   if( pic_scaling_list_present_flag )    pic_scaling_list_aps_id u(3)  }  if( picture_header_extension_present_flag ) {   ph_extension_length ue(v)   for( i = 0; i < ph_extension_length; i++)    ph_extension_data_byte[ i ] u(8)  }  rbsp_trailing_bits( ) }

-   -   With respect to Table 5, JVET-P2001 provides the following         semantics:     -   The PH contains information that is common for all slices of the         coded picture associated with the PH.     -   non_reference_picture_flag equal to 1 specifies the picture         associated with the PH is never used as a reference picture.         non_reference_picture_flag equal to 0 specifies the picture         associated with the PH may or may not be used as a reference         picture.     -   gdr_pic_flag equal to 1 specifies the picture associated with         the PH is a GDR picture. gdr_pic_flag equal to 0 specifies that         the picture associated with the PH is not a GDR picture.     -   no_output_of_prior_pics_flag affects the output of         previously-decoded pictures in the decoded picture buffer after         the decoding of a CLVSS picture that is not the first picture in         the bitstream as specified.     -   recovery_poc_cnt specifies the recovery point of decoded         pictures in output order. If the current picture is a GDR         picture that is associated with the PH and there is a picture         picA that follows the current GDR picture in decoding order in         the CLVS and that has PicOrderCntVal equal to the PicOrderCntVal         of the current GDR picture plus the value of recovery_poc_cnt,         the picture picA is referred to as the recovery point picture.         Otherwise, the first picture in output order that has         PicOrderCntVal greater than the PicOrderCntVal of the current         picture plus the value of recovery_poc_cnt is referred to as the         recovery point picture. The recovery point picture shall not         precede the current GDR picture in decoding order. The value of         recovery_poc_cnt shall be in the range of 0 to         MaxPicOrderCntLsb−1, inclusive.         -   NOTE—When gdr_enabled_flag is equal to 1 and PicOrderCntVal             of the current picture is greater than or equal to             RpPicOrdaCntVal of the associated GDR picture, the current             and subsequent decoded pictures in output order are exact             match to the corresponding pictures produced by starting the             decoding process from the previous IRAP picture, when             present, preceding the associated GDR picture in decoding             order.     -   ph_pic_parameter_set_id specifies the value of         pps_pic_parameter_set_id for the PPS in use. The value of         ph_pic_parameter_set_id shall be in the range of 0 to 63,         inclusive. It is a requirement of bitstream conformance that the         value of TemporalId of the PH shall be greater than or equal to         the value of TemporalId of the PPS that has         pps_pic_parameter_set_id equal to ph_pic_parameter_set_id.     -   ph_poc_msb_present_flag equal to 1 specifies that the syntax         element poc_msb_val is present in the PH.         ph_poc_msb_present_flag equal to 0 specifies that the syntax         element poc_msb_val is not present in the PH. When         vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is         equal to 0 and there is a picture in the current AU in a         reference layer of the current layer, the value of         ph_poc_msb_present_flag shall be equal to 0.     -   poc_msb_val specifies the POC MSB value of the current picture.         The length of the syntax element poc_msb_val is         poc_msb_len_minus1+1 bits.     -   ph_subpic_id_signalling_present_flag equal to 1 specifies that         subpicture ID mapping is signalled in the PH.         ph_subpic_id_signalling_present_flag equal to 0 specifies that         subpicture ID mapping is not signalled in the PH.     -   ph_subpic_id_len_minus1 plus 1 specifies the number of bits used         to represent the syntax element ph_subpic_id[i]. The value of         pic_subpic_id_len_minus1 shall be in the range of 0 to 15,         inclusive.     -   It is a requirement of bitstream conformance that the value of         ph_subpic_id_len_minus1 shall be the same for all PHs that are         referred to by coded pictures in a CLVS.     -   ph_subpic_id[i] specifies that subpicture ID of the i-th         subpicture. The length of the ph_subpic_id[i] syntax element is         ph_subpic_id_len_minus1+1 bits.     -   The list SubpicIdList[i] is derived as follows:

  for( i = 0; i <= sps_num_subpics_minus1; i++ )  SubpicIdList[ i ] = sps_subpic_id_present_flag ?   ( sps_subpic_id_signalling_present_flag ? sps_subpic_id[ i ] :   ( ph_subpic_id_signalling_present_flag ?    ph_subpic_id[ i ] : pps_subpic_id[ i ] ) ) : i

-   -   ph_loop_filter_across_virtual_boundaries_disabled_present_flag         equal to 1 specifies that the in-loop filtering operations are         disabled across the virtual boundaries in pictures associated to         the PH.         ph_loop_filter_across_virtual_boundaries_disabled_present_flag         equal to 0 specifies that no such disabling of in-loop filtering         operations is applied in pictures associated to the PH. The         in-loop filtering operations include the deblocking filter,         sample adaptive offset filter, and adaptive loop filter         operations. When not present, the value of         ph_loop_filter_across_virtual_boundaries_disabled_present_flag         is inferred to be equal to 0.     -   The parameter VirtualBoundariesDisabledFlag is derived as         follows:

VirtualBoundaiesDisabledFlag=sps_loop_filter_across_virtual_boundaries_disabled_present_flag∥ph_loop_filter_across_virtual_boundaries_disabled_present_flag

-   -   ph_numb_ver_virtual_boundaries specifies the number of         ph_virtual_boundaries_pos_x[i] syntax elements that are present         in the PH. When ph_num_ver_virtual_boundaries is not present, it         is inferred to be equal to 0.     -   The parameter VirtualBoundariesNumVer is derived as follows:

VirtualBoundariesNumVer=sps_loop_filter_across_virtual_boundaries_disabled_present_flag?sps_num_ver_virtual_boundaries: ph_num_ver_virtual_boundaries

-   -   ph_virtual_boundaries_pos_x[i] is used to compute the value of         VirtualBoundariesPosX[i], which specifies the location of the         i-th vertical virtual boundary in units of luma samples.         ph_virtual_boundaries_pos_x[i] shall be in the range of 1 to         Ceil(pic_width_in_luma_samples÷8)−1, inclusive.     -   The location of the vertical virtual boundary         VirtualBoundariesPosX[i] is derived as follows:

VirtualBoundariesPosX[i]=(sps_loop_filter_across_virtual_boundaries_disabled_present_flag?sps_virtual_boundaries_pos_x[i]: ph_virtual_boundaries_pos_x[i])*8

-   -   The distance between any two vertical virtual boundaries shall         be greater than or equal to CtbSizeY luma samples.     -   ph_num_hor_virtual_boundaries specifies the number of         ph_virtual_boundaries_pos_y[i] syntax elements that are present         in the PH. When ph_num_hor_virtual_boundaries is not present, it         is inferred to be equal to 0.     -   The parameter VirtualBoundariesNumHor is derived as follows:

VirtualBoundariesNumHor=sps_loop_filter_across_virtual_boundaries_disabled_present_flag?sps_num_hor_virtual_boundaries: ph_num_hor_virtual_boundaries

-   -   ph_virtual_boundaries_pos_y[i] is used to compute the value of         VirtualBoundariesPosY[i], which specifies the location of the         i-th horizontal virtual boundary in units of luma samples.         ph_virtual_boundaries_pos_y[i] shall be in the range of 1 to         Ceil(pic_height_in_luma_samples÷8)−1, inclusive.     -   The location of the horizontal virtual boundary         VirtualBoundariesPosY[i] is derived as follows:

VirtualBoundariesPosY[i]=(sps_loop_filter_across_virtual_boundaries_disabled_present_flag?sps_virtual_boundaries_pos_y[i]: ph_virtual_boundaries_pos_y[i])*8

-   -   The distance between any two horizontal virtual boundaries shall         be greater than or equal to CtbSizeY luma samples.     -   colour_plane_id specifies the colour plane associated with the         slices associated with the PH when separate_colour_plane_flag is         equal to 1. The value of colour_plane_id shall be in the range         of 0 to 2, inclusive. colour_plane_id values 0, 1 and 2         correspond to the Y, Cb and Cr planes, respectively.         -   NOTE—There is no dependency between the decoding processes             of pictures having different values of colour_plane_id.     -   pic_output_flag affects the decoded picture output and removal         processes as specified. When pic_output_flag is not present, it         is inferred to be equal to 1.     -   pic_rpl_present_flag equals 1 specifies that reference picture         list signalling is present in the PH. pic_rpl_present_flag         equals 0 specifies that reference picture list signalling is not         present in the PH and may be present in slice headers of slices         of the picture.     -   It is a requirement of bitstream conformance that the value of         pic_rpl_present_flag shall be equal to 0 when         sps_id_rpl_present_flag is equal to 0 and the picture associated         with the PH is an IDR picture.     -   pic_rpl_sps_flag[i] equal to 1 specifies that reference picture         list i for the picture associated with the PH is derived based         on one of the ref_pic_list_struct(listIdx, rplsIdx) syntax         structures with listIdx equal to i in the SPS.         ref_pic_list_sps_flag[i] equal to 0 specifies that reference         picture list i of the picture is derived based on the         ref_pic_list_struct(listIdx, rplsIdx) syntax structure with         listIdx equal to i that is directly included in the PH.     -   When pic_rpl_sps_flag[i] is not present, the following applies:         -   If num_ref_pic_lists_in_sps[i] is equal to 0, the value of             pic_rpl_sps_flag[i] is inferred to be equal to 0.         -   Otherwise if num_ref_pic_lists_in_sps[i] is greater than 0             and rpl1_idx_present_flag is equal to 0, the value of             pic_rpl_sps_flag[1] is inferred to be equal to             pic_rpl_sps_flag[0].         -   Otherwise, the value of pic_rpl_sps_flag[i] is inferred to             be equal to pps_ref_pic_list_sps_idc[i]−1.     -   pic_rpl_idx[i] specifies the index, into the list of the         ref_pic_list_struct(listIdx, rplsIdx) syntax structures with         listIdx equal to i included in the SPS, of the         ref_pic_list_struct(listIdx, rplsIdx) syntax structure with         listIdx equal to i that is used for derivation of reference         picture list i of the current picture. The syntax element         pic_rpl_idx[i] is represented by         Ceil(Log2(num_ref_pic_lists_in_sps[i])) bits. When not present,         the value of pic_rpl_idx[i] is inferred to be equal to 0. The         value of pic_rpl_idx[i] shall be in the range of 0 to         num_ref_pic_lists_in_sps[i]−1, inclusive. When         pic_rpl_sps_flag[i] is equal to 1 and         num_ref_pic_lists_in_sps[i] is equal to 1, the value of         pic_rpl_idx[i] is inferred to be equal to 0. When         pic_rpl_sps_flag[i] is equal to 1 and rpl1_idx_present_flag is         equal to 0, the value of pic_rpl_idx[1] is inferred to be equal         to pic_rpl_idx[0].     -   The variable PicRplsIdx[i] is derived as follows:

PicRplsIdx[i]=pic_rpl_sps_flag[i]?pic_rpl_idx[i]: num_ref_pic_lists_in_sps[i]

-   -   pic_poc_lsb_lt[i][j] specifies the value of the picture order         count modulo MaxPicOrderCntLsb of the j-th LTRP entry in the         i-th reference picture list for the picture associated with the         PH. The length of the pic_poc_lsb_lt[i][j] syntax element is         log2_max_pic_order_cnt_lsb_minus4+4 bits.     -   The variable PicPocLsbLt[i][j] is derived as follows:

PicPocLsbLt[i][j]=ltrp_in_slice_header_flag[i][PicRplsIdx[i]]?pic_poc_lsb_lt[i][j]: rpls_poc_lab_lt[listIdx][PicRplsIdx[i]][j]

-   -   pic_delta_poc_msb_present_flag[i][j] equal to 1 specifies that         pic_delta_poc_msb_cycle_lt[i][j] is present.         pic_delta_poc_msb_present_flag[i][j] equal to 0 specifies that         pic_delta_poc_msb_cycle_lt[i][j] is not present.     -   Let prevTid0Pic be the previous picture in decoding order that         has nuh_layer_id the same as the PH, has TemporalId equal to 0,         and is not a RASL or RADL picture. Let setOfPrevPocVals be a set         consisting of the following:         -   the PicOrderCntVal of prevTid0Pic,         -   the PicOrderCntVal of each picture that is referred to by             entries in RefPicList[0] or RefPicList[1] of prevTid0Pic and             has nuh_layer_id the same as the current picture,         -   the PicOrdaCntVal of each picture that follows prevTid0Pic             in decoding order, has nuh_layer_id the same as the current             picture, and precedes the current picture in decoding order.     -   When there is more than one value in setOfPrevPocVals for which         the value modulo MaxPicOrderCntLsb is equal to         PicPocLsbLt[i][j], the value of         pic_delta_poc_msb_present_flag[i][i] shall be equal to 1.     -   pic_delta_poc_msb_cycle_lt[i][j] specifies the value of the         variable PicFullPocLt[i][j] as follows:

  if( j = = 0 )  deltaPocMsbCycleLt[ i ][ j ] = pic_delta_poc_msb_cycle_lt[ i ][ j ] else  deltaPocMsbCycleLt[ i ][ j ] = pic_delta_poc_msb_cycle_lt[ i ][ j ] + deltaPocMsbCycleLt[ i ][ j − 1 ] PicFullPocLt[ i ][ j ] = PicOrderCntVal −  deltaPocMsbCycleLt[ i ][ j ] * MaxPicOrderCntLsb −   ( PicOrderCntVal & ( MaxPicOrderCntLsb − 1 ) ) + PicPocLsbLt[ i ][ j ]

-   -   The value of pic_detla_poc_msb_cycle_lt[i][j] shall be in the         range of 0 to 2^((32-log2_max_pic_order_cnt_lsb_minus4-4)),         inclusive. When not present, the value of         pic_delta_poc_msb_cycle_lt[i][j] is inferred to be equal to 0.     -   partition_constraints_override_flag equal to 1 specifies that         partition constraint parameters are present in the PH.         partition_constraints_override_flag equal to 0 specifies that         partition constraint parameters are not present in the PH. When         not present, the value of partition_constraints_override_flag is         inferred to be equal to 0.     -   pic_log2_diff_min_qt_min_cb_intra_slice_luma specifies the         difference between the base 2 logarithm of the minimum size in         luma samples of a luma leaf block resulting from quadtree         splitting of a CTU and the base 2 logarithm of the minimum         coding block size in luma samples for luma CUs in the slices         with slice_type equal to 2 (I) associated with the PH. The value         of pic_log2_diff_min_qt_min_cb_intra_slice_luma shall be in the         range of 0 to CtbLog2SizeY−MinCbLog2SizeY, inclusive. When not         present, the value of pic_log2_diff_min_qt_min_cb_luma is         inferred to be equal to         sps_log2_diff_min_qt_min_cb_intra_slice_luma.     -   pic_log2_diff_min_qt_min_cb_inter_slices specifies the         difference between the base 2 logarithm of the minimum size in         luma samples of a luma leaf block resulting from quadtree         splitting of a CTU and the base 2 logarithm of the minimum luma         coding block size in luma samples for luma CUs in the slices         with slice_type equal to 0 (B) or 1 (P) associated with the PH.         The value of pic_log2_diff_min_qt_min_cb_inter_slice shall be in         the range of 0 to CtbLog2SizeY−MinCbLog2SizeY, inclusive. When         not present, the value of pic_log2_diff_min_qt_min_cb_luma is         inferred to be equal to sps_log2_diff_min_qt_min_cb_inter_slice.     -   pic_max_mtt_hierarchy_depth_inter_slice specifies the maximum         hierarchy depth for coding units resulting from multi-type tree         splitting of a quadtree leaf in slices with slice_type equal to         0 (B) or 1 (P) associated with the PH. The value of         pic_max_mtt_hierarchy_depth_inter_slice shall be in the range of         0 to CtbLog2SizeY−MinCbLog2SizeY, inclusive. When not present,         the value of pic_max_mtt_hierarchy_depth_inter_slice is inferred         to be equal to sps_max_mtt_hierarchy_depth_inter_slice.     -   pic_max_mtt_hierarchy_depth_intra_slice_luma specifies the         maximum hierarchy depth for coding units resulting from         multi-type tree splitting of a quadtree leaf in slices with         slice_type equal to 2 (I) associated with the PH. The value of         pic_max_mtt_hierarchy_depth_intra_slice_luma shall be in the         range of 0 to CtbLog2SizeY−MinCbLog2SizeY, inclusive. When not         present, the value of         pic_max_mtt_hierarchy_depth_intra_slice_luma is inferred to be         equal to sps_max_mtt_hierarchy_depth_intra_slice_luma.     -   pic_log2_diff_max_bt_min_qt_intra_slice_luma specifies the         difference between the base 2 logarithm of the maximum size         (width or height) in luma samples of a luma coding block that         can be split using a binary split and the minimum size (width or         height) in luma samples of a luma leaf block resulting from         quadtree splitting of a CTU in slices with slice_type equal to         2 (I) associated with the PH. The value of         pic_log2_diff_max_bt_min_qt_intra_slice_luma shall be in the         range of 0 to CtbLog2SizeY−MinQtLog2SizeIntraY, inclusive. When         not present, the value of         pic_log2_diff_max_bt_min_qt_intra_slice_luma is inferred to be         equal to sps_log2_diff_max_bt_min_qt_intra_slice_luma.     -   pic_log2_diff_max_tt_min_qt_intra_slice_luma specifies the         difference between the base 2 logarithm of the maximum size         (width or height) in luma samples of a luma coding block that         can be split using a ternary split and the minimum size (width         or height) in luma samples of a luma leaf block resulting from         quadtree splitting of a CTU in slices with slice_type equal to         2 (I) associated with the PH. The value of         pic_log2_diff_max_tt_min_qt_intra_slice_luma shall be in the         range of 0 to CtbLog2SizeY−MinQtLog2SizeIntraY, inclusive. When         not present, the value of         pic_log2_diff_max_tt_min_qt_intra_slice_luma is inferred to be         equal to sps_log2_diff_max_tt_min_qt_intra_slice_luma.     -   pic_log2_diff_max_bt_min_qt_inter_slice specifies the difference         between the base 2 logarithm of the maximum size (width or         height) in luma samples of a luma coding block that can be split         using a binary split and the minimum size (width or height) in         luma samples of a luma leaf block resulting from quadtree         splitting of a CTU in the slices with slice_type equal to 0 (B)         or 1 (P) associated with the PH. The value of         pic_log2_diff_max_bt_min_qt_inter_slice shall be in the range of         0 to CtbLog2SizeY−MinQtLog2SizeInterY, inclusive. When not         present, the value of pic_log2_diff_max_bt_min_qt_inter_slice is         inferred to be equal to sps_log2_diff_max_bt_min_qt_inter_slice.     -   pic_log2_diff_max_tt_min_qt_inter_slice specifies the difference         between the base 2 logarithm of the maximum size (width or         height) in luma samples of a luma coding block that can be split         using a ternary split and the minimum size (width or height) in         luma samples of a luma leaf block resulting from quadtree         splitting of a CTU in slices with slice_type equal to 0 (B) or         1 (P) associated with the PH. The value of         pic_log2_diff_max_tt_min_qt_inter_slice shall be in the range of         0 to CtbLog2SizeY−MinQtLog2SizeInterY, inclusive. When not         present, the value of pic_log2_diff_max_tt_min_qt_inter_slice is         inferred to be equal to sps_log2_diff_max_tt_min_qt_inter_slice.     -   pic_log2_diff_min_qt_min_cb_intra_slice_chroma specifies the         difference between the base 2 logarithm of the minimum size in         luma samples of a chroma leaf block resulting from quadtree         splitting of a chroma CTU with treeType equal to         DUAL_TREE_CHROMA and the base 2 logarithm of the minimum coding         block size in luma samples for chroma CUs with treeType equal to         DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I)         associated with the PH. The value of         pic_log2_diff_min_qt_min_cb_intra_slice_chroma shall be in the         range of 0 to CtbLog2SizeY−MinCbLog2SizeY, inclusive. When not         present, the value of         pic_log2_diff_min_qt_min_cb_intra_slice_chroma is inferred to be         equal to sps_log2_diff_min_qt_min_cb_intra_slice_chroma.     -   pic_max_mtt_hierarchy_depth_intra_slice_chroma specifies the         maximum hierarchy depth for chroma coding units resulting from         multi-type tree splitting of a chroma quadtree leaf with         treeType equal to DUAL_TREE_CHROMA in slices with slice_type         equal to 2 (I) associated with the PH. The value of         pic_max_mtt_hierarchy_depth_intra_slice_chroma shall be in the         range of 0 to CtbLog2SizeY−MinCbLog2SizeY, inclusive. When not         present, the value of         pic_max_mtt_hierarchy_depth_intra_slice_chroma is inferred to be         equal to sps_max_mtt_hierarchy_depth_intra_slice_chroma.     -   pic_log2_diff_max_bt_min_qt_intra_slice_chroma specifies the         difference between the base 2 logarithm of the maximum size         (width or height) in luma samples of a chroma coding block that         can be split using a binary split and the minimum size (width or         height) in luma samples of a chroma leaf block resulting from         quadtree splitting of a chroma CTU with treeType equal to         DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I)         associated with the PH. The value of         pic_log2_diff_max_bt_min_qt_intra_slice_chroma shall be in the         range of 0 to CtbLog2SizeY−MinQtLog2SizeIntraC, inclusive. When         not present, the value of         pic_log2_diff_max_bt_min_qt_intra_slice_chroma is inferred to be         equal to sps_log2_diff_max_bt_min_qt_intra_slice_chroma.     -   pic_log2_diff_max_tt_min_qt_intra_slice_chroma specifies the         difference between the base 2 logarithm of the maximum size         (width or height) in luma samples of a chroma coding block that         can be split using a ternary split and the minimum size (width         or height) in luma samples of a chroma leaf block resulting from         quadtree splitting of a chroma CTU with treeType equal to         DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I)         associated with the PH. The value of         pic_log2_diff_max_tt_min_qt_intra_slice_chroma shall be in the         range of 0 to CtbLog2SizeY−MinQtLog2SizeIntraC, inclusive. When         not present, the value of         pic_log2_diff_max_tt_min_qt_intra_slice_chroma is inferred to be         equal to sps_log2_diff_max_tt_min_qt_intra_slice_chroma     -   pic_cu_qu_delta_subdiv_intra_slice specifies the maximum         cbSubdiv value of coding units in intra slice that convey         cu_qp_delta_abs and cu_qp_delta_sign_flag. The value of         pic_cu_qp_delta_subdiv_intra_slice shall be in the range of 0 to         2*(CtbLog2SizeY−MinQtLog2SizeIntraY+pic_max_mtt_hierarchy_depth_intra_slice_luma),         inclusive.     -   When not present, the value of         pic_cu_qp_delta_subdiv_intra_slice is inferred to be equal to 0.     -   pic_cu_qp_delta_subdiv_inter_slice specifies the maximum         cbSubdiv value of coding units that in inter slice convey         cu_qp_delta_abs and cu_qp_delta_sign_flag. The value of         pic_cu_qp_delta_subdiv_inter_slice shall be in the range of 0 to         2*(CtbLog2SizeY−MinQtLog2SizeInterY+pic_max_mtt_hierarchy_depth_inter_slice),         inclusive.     -   When not present, the value of         pic_cu_qp_delta_subdiv_inter_slice is inferred to be equal to 0.     -   pic_cu_chroma_qp_offset_subdiv_intra_slice specifies the maximum         cbSubdiv value of coding units in intra slice that convey         cu_chroma_qp_offset_flag. The value of         pic_cu_chroma_qp_offset_subdiv_intra_slice shall be in the range         of 0 to         2*(CtbLog2SizeY−MinQtLog2SizeIntraY+pic_max_mtt_hierarchy_depth_intra_slice_luma),         inclusive.     -   When not present, the value of         pic_cu_chroma_qp_offset_subdiv_intra_slice is inferred to be         equal to 0.     -   pic_cu_chroma_qp_offset_subdiv_inter_slice specifies the maximum         cbSubdiv value of coding units in inter slice that convey         cu_chroma_qp_offset_flag. The value of         pic_cu_chroma_qp_offset_subdiv_inter_slice shall be in the range         of 0 to         2*(CtbLog2SizeY−MinQtLog2SizeInterY+pic_max_mtt_hierarchy_depth_inter_slice),         inclusive.     -   When not present, the value of         pic_cu_chroma_qp_offset_subdiv_inter_slice is inferred to be         equal to 0.     -   pic_temporal_mvp_enabled_flag specifies whether temporal motion         vector predictors can be used for inter prediction for slices         associated with the PH. If pic_temporal_mvp_enabled_flag is         equal to 0, the syntax elements of the slices associated with         the PH shall be constrained such that no temporal motion vector         predictor is used in decoding of the slices. Otherwise         (pic_temporal_mvp_enabled_flag is equal to 1), temporal motion         vector predictors may be used in decoding of the slices         associated with the PH. When not present, the value of         pic_temporal_mvp_enabled_flag is inferred to be equal to 0.     -   mvd_l1_zero_flag equal to 1 indicates that the mvd_coding(x0,         y0, 1) syntax structure is not parsed and MvdL1[x0][y0][compIdx]         and MvdL1[x0][y0][cpIdx][compIdx] are set equal to 0 for         compIdx=0 . . . 1 and cpIdx=0 . . . 2. mvd_l1_zero_flag equal to         0 indicates that the mvd_coding(x0, y0, 1) syntax structure is         parsed. When not present, the value of mvd_l1_zero_flag is         inferred to be equal to pps_mvd_l1_zero_idc−1.     -   pic_six_minus_num_merge_cand specifies the maximum number of         merging motion vector prediction (MVP) candidates supported in         the slices associated with the PH subtracted from 6. The maximum         number of merging MVP candidates, MaxNumMergeCand is derived as         follows:

MaxNumMergeCand=6−picsix_minus_max_num_merge_cand

-   -   The value of MaxNumMergeCand shall be in the range of 1 to 6,         inclusive. When not present, the value of         pic_six_minus_max_num_merge_cand is inferred to be equal to         pps_six_minus_max_num_merge_cand_plus1−1.     -   pic_five_minus_max_num_subblock_merge_cand specifies the maximum         number of subblock-based merging motion vector prediction (MVP)         candidates supported in the slice subtracted from 5. When not         present, the value of pic_five_minus_max_num_subblock_merge_cand         is inferred to be equal to 5−(sps_sbtmvp_enabled_flag &&         pic_temporal_mvp_enabled_flag).     -   The maximum number of subblock-based merging MVP candidates,         MaxNumSubblockMergeCand is derived as follows:

MaxNumSubblockMergeCand=5−pic_five_minus_max_num_subblock_merge_cand

-   -   The value of MaxNumSubblockMergeCand shall be in the range of 0         to 5, inclusive.     -   pic_fpel_mmvd_enabled_flag equal to 1 specifies that merge mode         with motion vector difference uses integer sample precision in         the slices associated with the PH. pic_fpel_mmvd_enabled_flag         equal to 0 specifies that merge mode with motion vector         difference can use fractional sample precision in the slices         associated with the PH. When not present, the value of         pic_fpel_mmvd_enabled_flag is inferred to be 0.     -   pic_disable_bdof_flag equal to 1 specifies that bi-directional         optical flow inter prediction based inter bi-prediction is         disabled in the slices associated with the PH.         pic_disable_bdof_flag equal to 0 specifies that bi-directional         optical flow inter prediction based inter bi-prediction may or         may not be enabled in the slices associated with the PH.     -   When pic_disable_bdof_flag is not present, the following         applies:         -   If sps_bdof_enabled_flag is equal to 1, the value of             pic_disable_bdof_flag is inferred to be equal to 0.         -   Otherwise (sps_bdof_enabled_flag is equal to 0), the value             of pic_disable_bdof_flag is inferred to be equal to 1.     -   pic_disable_dmvr_flag equal to 1 specifies that decoder motion         vector refinement based inter bi-prediction is disabled in the         slices associated with the PH. pic_disable_dmvr_flag equal to 0         specifies that decoder motion vector refinement based inter         bi-prediction may or may not be enabled in the slices associated         with the PH. When not present, the value of         pic_disable_dmvr_flag is inferred to be 1.     -   When pic_disable_dmvr_flag is not present, the following         applies:         -   If sps_dmvr_enabled_flag is equal to 1, the value of             pic_disable_dmvr_flag is inferred to be equal to 0.         -   Otherwise (sps_dmvr_enabled_flag is equal to 0), the value             of pic_disable_dmvr_flag is inferred to be equal to 1.     -   pic_disable_prof_flag equal to 1 specifies that prediction         refinement with optical flow is disabled in the slices         associated with the PH. pic_disable_prof_flag equal to 0         specifies that prediction refinement with optical flow may or         may not be enabled in the slices associated with the PH. When         not present, the value of pic_disable_prof_flag is inferred to         be 1.     -   When pic_disable_prof_flag is not present, the following         applies:         -   If sps_affine_prof_enabled_flag is equal to 1, the value of             pic_disable_prof_flag is inferred to be equal to 0.         -   Otherwise (sps_affine_prof_enabled_flag is equal to 0), the             value of pic_disable_prof_flag is inferred to be equal to 1.     -   pic_max_num_merge_cand_minus_max_num_triangle_cand specifies the         maximum number of triangular merge mode candidates supported in         the slices associated with the pictur header subtracted from         MaxNumMergeCand.     -   When pic_max_num_merge_cand_minus_max_num_triangle_cand is not         present, and sps_triangle_enabled_flag is equal to 1 and         MaxNumMergeCand greater than or equal to 2,         pic_max_num_merge_cand_minus_max_num_triangle_cand is inferred         to be equal to         pps_max_num_merge_cand_minus_max_num_triangle_cand_plus1−1.     -   The maximum number of triangular merge mode candidates,         MaxNumTriangleMergeCand is derived as follows:

MaxNumTriangleMergeCand=MaxNumMergeCand −pic_max_num_merge_cand_minus_max_num_triangle_cand

-   -   When pic_max_num_merge_cand_minus_max_num_triangle_cand is         present, the value of MaxNumTriangleMergeCand shall be in the         range of 2 to MaxNumMergeCand, inclusive. When         pic_max_num_merge_cand_minus_max_num_triangle_cand is not         present, and (sps_triangle_enabled_flag is equal to 0 or         MaxNumMergeCand is less than 2), MaxNumTriangleMergeCand is set         equal to 0.     -   When MaxNumTriangleMergeCand is equal to 0, triangle merge mode         is not allowed for the slices associated with the PH.     -   pic_six_minus_max_num_ibc_merge_cand specifies the maximum         number of IBC merging block vector prediction (BVP) candidates         supported in the slices associated with the PH subtracted         from 6. The maximum number of IBC merging BVP candidates,         MaxNumIbcMergeCand is derived as follows:

MaxNumIbcMergeCand=6−pic_six_minus_max_num_ibc_merge_cand

-   -   The value of MaxNumIbcMergeCand shall be in the range of 1 to 6,         inclusive.     -   pic_joint_cbcr_sign_flag specifies whether, in transform units         with tu_joint_cbcr_residual_flag[x0][y0] equal to 1, the         co-located residual samples of both chroma components have         inverted signs. When tu_joint_cbcr_residual_flag[x0][y0] equal         to 1 for a transform unit, pic_joint_cbcr_sign_flag equal to 0         specifies that the sign of each residual sample of the Cr (or         Cb) component is identical to the sign of the co-located Cb (or         Cr) residual sample and pic_joint_cbcr_sign_flag equal to 1         specifies that the sign of each residual sample of the Cr (or         Cb) component is given by the inverted sign of the co-located Cb         (or Cr) residual sample.     -   pic_sao_enabled_present_flag equal to 1 specifies that         pic_sao_luma_flag and pic_sao_chroma_flag are present in the PH.         pic_sao_enabled_present_flag equal to 0 specifies that         pic_sao_luma_flag and pic_sao_chroma_flag are not present in the         PH. When pic_sao_enabled_present_flag is not present, it is         inferred to be equal to 0.     -   pic_sao_luma_flag equal to 1 specifies that SAO is enabled for         the luma component in all slices associated with the PH;         pic_sao_luma_flag equal to 0 specifies that SAO for the luma         component may be disabled for one, or more, or all slices         associated with the PH. When pic_sao_luma_flag is not present,         it is inferred to be equal to 0.     -   pic_sao_chroma_flag equal to 1 specifies that SAO is enabled for         the chroma component in all slices associated with the PH;         pic_sao_chroma_flag equal to 0 specifies that SAO for chroma         component may be disabled for one, or more, or all slices         associated with the PH. When pic_sao_chroma_flag is not present,         it is inferred to be equal to 0.     -   pic_alf_enabled_present_flag equal to 1 specifies that         pic_alf_enabled_flag, pic_num_alf_aps_ids_luma,         pic_alf_aps_id_luma[i], pic_alf_chroma_idc, and         pic_alf_aps_id_chroma are present in the PH.         pic_alf_enabled_present_flag equal to 0 specifies that         pic_alf_enabled_flag, pic_num_alf_aps_ids_luma,         pic_alf_aps_id_luma[i], pic_alf_chroma_idc, and         pic_alf_aps_id_chroma are not present in the PH. When         pic_alf_enabled_present_flag is not present, it is inferred to         be equal to 0.     -   pic_alf_enabled_flag equal to 1 specifies that adaptive loop         filter is enabled for all slices associated with the PH and may         be applied to Y, Cb, or Cr colour component in the slices.         pic_alf_enabled_flag equal to 0 specifies that adaptive loop         filter may be disabled for one, or more, or all slices         associated with the PH. When not present, pic_alf_enabled_flag         is inferred to be equal to 0.     -   pic_num_alf_aps_ids_luma specifies the number of ALF APSs that         the slices associated with the PH refers to.     -   pic_alf_aps_id_luma[i] specifies the adaptation_parameter_set_id         of the i-th ALF APS that the luma component of the slices         associated with the PH refers to.     -   The value of alf_luma_filter_signal_flag of the APS NAL unit         having aps_params_type equal to ALF_APS and         adaptation_parameter_set_id equal to pic_alf_aps_id_luma[i]         shall be equal to 1.     -   pic_alf_chroma_idc equal to 0 specifies that the adaptive loop         filter is not applied to Cb and Cr colour components.         pic_alf_chroma_idc equal to 1 indicates that the adaptive loop         filter is applied to the Cb colour component. pic_alf_chroma_idc         equal to 2 indicates that the adaptive loop filter is applied to         the Cr colour component. pic_alf_chroma_idc equal to 3 indicates         that the adaptive loop filter is applied to Cb and Cr colour         components. When pic_alf_chroma_idc is not present, it is         inferred to be equal to 0.     -   pic_alf_aps_id_chroma specifies the adaptation_parameter_set_id         of the ALF APS that the chroma component of the slices         associated with the PH refers to.     -   The value of alf_chroma_filter_signal_flag of the APS NAL unit         having aps_params_type equal to ALF_APS and         adaptation_parameter_set_id equal to pic_alf_aps_id_chroma shall         be equal to 1.     -   pic_dep_quant_enabled_flag equal to 0 specifies that dependent         quantization is disabled for slices associated with the PH.         pic_dep_quant_enabled_flag equal to 1 specifies that dependent         quantization is enabled for slices associated with the PH. When         not present, the value of pic_dep_quant_enabled_flag is inferred         to be equal to pps_dep_quant_enable_idc−1.     -   sign_data_hiding_enabled_flag equal to 0 specifies that sign bit         hiding is disabled. sign_data_hiding_enabled_flag equal to 1         specifies that sign bit hiding is enabled. When         sign_data_hiding_enabled_flag is not present, it is inferred to         be equal to 0.     -   pic_deblocking_filter_ovrride_present_flag equal to 1 specifies         that pic_deblocking_filter_override_flag is present in the PH.         pic_deblocking_filter_override_present_flag equal to 0 specifies         that pic_deblocking_filter_override_flag is not present in the         PH. When pic_deblocking_filter_override_present_flag is not         present, it is inferred to be equal to 0.     -   pic_deblocking_filter_override_flag equal to 1 specifies that         deblocking parameters are present in the PH.         pic_deblocking_filter_override_flag equal to 0 specifies that         deblocking parameters are not present in the PH. When not         present, the value of pic_pic_deblocking_filter_override_flag is         inferred to be equal to 0.     -   pic_deblocking_filter_disabled_flag equal to 1 specifies that         the operation of the deblocking filter is not applied for the         slices associated with the PH.         pic_deblocking_filter_disabled_flag equal to 0 specifies that         the operation of the deblocking filter is applied for the slices         associated with the PH. When pic_deblocking_filter_disabled_flag         is not present, it is inferred to be equal to         pps_deblocking_filter_disabled_flag.     -   pic_beta_offset_div2 and pic_tc_offset_div2 specify the         deblocking parameter offsets for ß and tC (divided by 2) for the         slices associated with the PH. The values of         pic_beta_offset_div2 and pic_tc_offset_div2 shall both be in the         range of −6 to 6, inclusive. When not present, the values of         pic_beta_offset_div2 and pic_tc_offset_div2 are inferred to be         equal to pps_beta_offset_div2 and pps_tc_offset_div2,         respectively.     -   pic_lmcs_enabled_flag equal to 1 specifies that luma mapping         with chroma scaling is enabled for all slices associated with         the PH. pic_lmcs_enabled_flag equal to 0 specifies that luma         mapping with chroma scaling may be disabled for one, or more, or         all slices associated with the PH. When not present, the value         of pic_lmcs_enabled_flag is inferred to be equal to 0.     -   pic_lmcs_aps_id specifies the adaptation_parameter_set_id of the         LMCS APS that the slices associated with the PH refers to. The         TemporalId of the APS NAL unit having aps_params_type equal to         LMCS_APS and adaptation_parameter_set_id equal to         pic_lmcs_aps_id shall be less than or equal to the TemporalId of         the picture associated with PH.     -   pic_chroma_residual_scale_flag equal to 1 specifies that chroma         residual scaling is enabled for the all slices associated with         the PH. pic_chroma_residual_scale_flag equal to 0 specifies that         chroma residual scaling may be disabled for one, or more, or all         slices associated with the PH. When         pic_chroma_residual_scale_flag is not present, it is inferred to         be equal to 0.     -   pic_scaling_list_present_flag equal to 1 specifies that the         scaling list data used for the slices associated with the PH is         derived based on the scaling list data contained in the         referenced scaling list APS. pic_scaling_list_present_flag equal         to 0 specifies that the scaling list data used for the slices         associated with the PH is the default scaling list data derived         specified. When not present, the value of         pic_scaling_list_present_flag is inferred to be equal to 0.     -   pic_scaling_list_aps_id specifies the         adaptation_parameter_set_id of the scaling list APS. The         TemporalId of the APS NAL unit having aps_params_type equal to         SCALING_APS and adaptation_parameter_set_id equal to         pic_scaling_list_aps_id shall be less than or equal to the         TemporalId of the picture associated with PH.     -   ph_extension_length specifies the length of the PH extension         data in bytes, not including the bits used for signalling         ph_extension_length itself. The value of ph_extension_length         shall be in the range of 0 to 256, inclusive. When not present,         the value of ph_extension_length is inferred to be equal to 0.     -   ph_extension_data_byte may have any value. Decoders conforming         to this version of this Specification shall ignore the value of         ph_extension_data_byte. Its value does not affect decoder         conformance to profiles specified in this version of         specification.     -   As provided in Table 2, a NAL unit may include coded slices of         pictures. A slice syntax structure includes slice_header( )         syntax structure and a slice_data( ) syntax structure. Table 6         illustrates the syntax of the slice header provided in         JVET-P2001.

TABLE 6 Descriptor slice_header( ) {  slice_pic_order_cnt_lsb u(v)  if( subpics_present_flag )   slice_subpic_id u(v)  if( rect_slice_flag || NumTilesInPic > 1 )   slice_address u(v)  if( !rect_slice_flag && NumTilesInPic > 1 )   num_tiles_in_slice_minus1 ue(v)  slice_type ue(v)  if( !pic_rpl_present_flag &&( ( nal_unit_type != IDR_W_RADL && nal_unit_type !=        IDR_N_LP ) || sps_idr_rpl_present_flag ) ) {   for( i = 0; i < 2; i++ ) {    if( num_ref_pic_lists_in_sps[ i ] > 0 && !pps_ref_pic_list_sps_idc[ i ] &&          ( i = = 0 || ( i = = 1 && rpl1_idx_present_flag ) ) )     slice_rpl_sps_flag[ i ] u(1)    if( slice_rpl_sps_flag[ i ] ) {     if( num_ref_pic_lists_in_sps[ i ] > 1 &&         ( i = = 0 || ( i = = 1 && rpl1_idx_present_flag ) ) )       slice_rpl_idx[ i ] u(v)    } else     ref_pic_list_struct( i, num_ref_pic_lists_in_sps[ i ] )    for( j = 0; j < NumLtrpEntries[ i ][ RplsIdx[ i ] ]; j++ ) {     if( ltrp_in_slice_header_flag[ i ][ RplsIdx[ i ] ] )      slice_poc_lsb_lt[ i ][ j ] u(v)     slice_delta_poc_msb_present_flag[ i ][ j ] u(1)     if( slice_delta_poc_msb_present_flag[ i ][ j ] )      slice_delta_poc_msb_cycle_lt[ i ][ j ] ue(v)    }   }  }  if( pic_rpl_present_flag || ( ( nal_unit_type != IDR_W_RADL && nal_unit_type !=     IDR_N_LP ) || sps_idr_rpl_present_flag ) ) {   if( ( slice_type != I && num_ref_entries[ 0 ][ RplsIdx[ 0 ] ] > 1 ) ||    ( slice_type = = B && num_ref_entries[ 1 ][ RplsIdx[ 1 ] ] > 1 ) ) {    num_ref_idx_active_override_flag u(1)    if( num_ref_idx_active_override_flag )     for( i = 0; i < ( slice_type = = B ? 2: 1 ); i++ )      if( num_ref_entries[ i ][ RplsIdx[ i ] ] > 1 )       num_ref_idx_active_minus1[ i ] ue(v)   }  }  if( slice_type != I ) {   if( cabac_init_present_flag )    cabac_init_flag u(1)   if( pic_temporal_mvp_enabled_flag ) {    if( slice_type = = B && !pps_collocated_from_l0_idc )     collocated_from_l0_flag u(1)    if( ( collocated_from_l0_flag && NumRefIdxActive[ 0 ] > 1 ) ||     ( !collocated_from_l0_flag && NumRefIdxActive[ 1 ] > 1 ) )     collocated_ref_idx ue(v)   }   if( ( pps_weighted_pred_flag && slice_type = = P ) ||    ( pps_weighted_bipred_flag && slice_type = = B ) )    pred_weight_table( )  }  slice_qp_delta se(v)  if( pps_slice_chroma_qp_offsets_present_flag ) {   slice_cb_qp_offset se(v)   slice_cr_qp_offset se(v)   if( sps_joint_cbcr_enabled_flag )    slice_joint_cbcr_qp_offset se(v)  }  if( sps_sao_enabled_flag && !pic_sao_enabled_present_flag ) {   slice_sao_luma_flag u(1)   if( ChromaArrayType != 0 )    slice_sao_chroma_flag u(1)  }  if( sps_alf_enabled_flag && !pic_alf_enabled_present_flag ) {   slice_alf_enabled_flag u(1)   if( slice_alf_enabled_flag ) {    slice_num_alf_aps_ids_luma u(3)    for( i = 0; i < slice_num_alf_aps_ids_luma; i++ )     slice_alf_aps_id_luma[ i ] u(3)    if( ChromaArrayType != 0 )     slice_alf_chroma_idc u(2)    if( slice_alf_chroma_idc )     slice_alf_aps_id_chroma u(3)   }  }  if( deblocking_filter_override_enabled_flag &&      !pic_deblocking_filter_override_present_flag )   slice_deblocking_filter_override_flag u(1)  if( slice_deblocking_filter_override_flag ) {   slice_deblocking_filter_disabled_flag u(1)   if( !slice_deblocking_filter_disabled_flag ) {   slice_beta_offset_div2 se(v)   slice_tc_offset_div2 se(v)   }  }  if( entry_point_offsets_present_flag && NumEntryPoints > 0 ) {   offset_len_minus1 ue(v)   for( i = 0; i < NumEntryPoints; i++ )    entry_point_offset_minus1[ i ] u(v)  }  if( slice_header_extension_present_flag ) {   slice_header_extension_length ue(v)   for( i = 0; i < slice_header_extension_length; i++)    slice_header_extension_data_byte[ i ] u(8)  }  byte_alignment( ) }

-   -   With respect to Table 6, JVET-P2001 provides the following         semantics:     -   When present, the value of the slice header syntax element         slice_pic_order_cnt_lsb shall be the same in all slice headers         of a coded picture.     -   The variable CuQpDeltaVal, specifying the difference between a         luma quantization parameter for the coding unit containing         cu_qp_delta_abs and its prediction, is set equal to 0. The         variables CuQpOffset_(Cb), CuQpOffset_(Cr), and         CuQpOffset_(CbCr), specifying values to be used when determining         the respective values of the Qp′_(Cb), Qp′_(Cr), and Qp′_(CbCr)         quantization parameters for the coding unit containing         cu_chroma_qp_offset_flag, are all set equal to 0.     -   slice_pic_order_cnt_lsb specifies the picture order count modulo         MaxPicOrderCntLsb for the current picture. The length of the         slice_pic_order_cnt_lsb syntax element is         log2_max_pic_order_cnt_lsb_minus4+4 bits. The value of the         slice_pic_order_cnt_lsb shall be in the range of 0 to         MaxPicOrderCntLsb=1, inclusive.     -   When the current picture is a GDR picture, the variable         RpPicOrderCntVal is derived as follows:

RpPicOrderCntVal=PicOrderCntVal+recovery_poc_cnt

-   -   slice_subpic_id specifies the subpicture identifier of the         subpicture that contains the slice. If slice_subpic_id is         present, the value of the variable SubPicIdx is derived to be         such that SubpicIdList[SubPicIdx] is equal to slice_subpic_id.         Otherwise (slice_subpic_id is not present), the variable         SubPicIdx is derived to be equal to 0. The length of         slice_subpic_id, in bits, is derived as follows:         -   If sps_subpic_id_signalling_present_flag is equal to 1, the             length of slice_subpic_id is equal to             sps_subpic_id_len_minus1+1.         -   Otherwise, if ph_subpic_id_signalling_present_flag is equal             to 1, the length of slice_subpic_id is equal to             ph_subpic_id_len_minus1+1.         -   Otherwise, if ph_subpic_id_signalling_present_flag is equal             to 1, the length of slice_subpic_id is equal to             pps_subpic_id_len_minus1+1.         -   Otherwise, the length of slice_subpic_id is equal to             Ceil(Log2 (sps_num_subpics_minus1+1)).     -   slice_address specifies the slice address of the slice. When not         present, the value of slice_address is inferred to be equal to         0.     -   If rect_slice_flag is equal to 0, the following applies:         -   The slice address is the raster scan tile index.         -   The length of slice_address is Ceil(Log2 (NumTilesInPic))             bits.         -   The value of slice_address shall be in the range of 0 to             NumTilesInPic−1, inclusive.     -   Otherwise (rect_slice_flag is equal to 1), the following         applies:         -   The slice address is the slice index of the slice within the             SubPicIdx-th subpicture.         -   The length of slice_address is             Ceil(Log2(NumSlicesInSubpic[SubPicIdx])) bits.         -   The value of slice_address shall be in the range of 0 to             NumSlicesInSubpic[SubPicIdx]−1, inclusive.     -   It is a requirement of bitstream conformance that the following         constraints apply:         -   If rect_slice_flag is equal to 0 or subpics_present_flag is             equal to 0, the value of slice_address shall not be equal to             the value of slice_address of any other coded slice NAL unit             of the same coded picture.         -   Otherwise, the pair of slice_subpic_id and slice_address             values shall not be equal to the pair of slice_subpic_id and             slice_address values of any other coded slice NAL unit of             the same coded picture.         -   When rect_slice_flag is equal to 0, the slices of a picture             shall be in increasing order of their slice_address values.         -   The shapes of the slices of a picture shall be such that             each CTU, when decoded, shall have its entire left boundary             and entire top boundary consisting of a picture boundary or             consisting of boundaries of previously decoded CTU(s).         -   For any two subpictures subpicA and subpicB, when the index             of subpicA is less than the index of subpicB, any coded NAL             unit of subPicA shall succeed any coded NAL unit of subPicB             in decoding order.         -   The shapes of the subpictures of a picture shall be such             that each subpicture, when decoded, shall have its entire             left boundary and entire top boundary consisting of picture             boundaries or consisting of boundaries of previously decoded             subpictures.     -   num_tiles_in_slice_minus1 plus 1, when present, specifies the         number of tiles in the slice. The value of         num_tiles_in_slice_minus1 shall be in the range of 0 to         NumTilesInPic−1, inclusive. The variable NumCtuInCurrSlice,         which specifies the number of CTUs in the current slice, and the         list CtbAddrInCurrSlice[i], for i ranging from 0 to         NumCtuInCurrSlice−1, inclusive, specifying the picture raster         scan address of the i-th CTB within the slice, are derived as         follows:

  if( rect_slice_flag ) {  picLevelSliceIdx = SliceSubpicToPicIdx[ SubPicIdx ][ slice_address ]  NumCtuInCurrSlice = NumCtuInSlice[ picLevelSliceIdx ]  for( i = 0; i < NumCtuInCurrSlice; i++ )   CtbAddrInCurrSlice[ i ] = CtbAddrInSlice[ picLevelSliceIdx ][ i ] } else {  NumCtuInCurrSlice = 0  for( tileIdx = slice_address; tileIdx <= slice_address +  num_tiles_in_slice_minus1[ i ]; tileIdx++ ) {   tileX = tileIdx % NumTileColumns   tileY = tileIdx / NumTileColumns   for( ctbY = tileRowBd[ tileY ]; ctbY < tileRowBd[ tileY + 1 ]; ctbY++ ) {    for( ctbX = tileColBd[ tileX ]; ctbX < tileColBd[ tileX + 1 ]; ctbX++ ) {     CtbAddrInCurrSlice[ NumCtuInCurrSlice ] = ctbY * PicWidthInCtb + ctbX     NumCtuInCurrSlice++    }   }  } }

-   -   The variables SubPicLeftBoundaryPos, SubPicTopBoundaryPos,         SubPicRightBoundaryPos, and SubPicBotBoundaryPos are derived as         follows:

  if( subpic_treated_as_pic_flag[ SubPicIdx ] ) {  SubPicLeftBoundaryPos = subpic_ctu_top_  left_x[ SubPicIdx ] * CtbSizeY  SubPicRightBoundaryPos = Min( pic_  width_max_in_luma_samples − 1,  ( subpic_ctu_top_left_x[ SubPicIdx ] + subpic_width_  minus1[ SubPicIdx ] + 1 ) * CtbSizeY − 1 )  SubPicTopBoundaryPos = subpic_ctu_top_  left_y[ SubPicIdx ] *CtbSizeY  SubPicBotBoundaryPos = Min( pic_  height_max_in_luma_samples − 1,  ( subpic_ctu_top_left_y[ SubPicIdx ] + subpic_height_  minus1[ SubPicIdx ] + 1 ) * CtbSizeY − 1) }

-   -   slice_type specifies the coding type of the slice according to         Table 7.

TABLE 7 slice_type Name of slice_type 0 B (B slice) 1 P (P slice) 2 I (I slice)

-   -   When nal_unit_type is a value of nal_unit_type in the range of         IDR_W_RADL to CRA_NUT inclusive, and the current picture is the         first picture in an access unit, slice_type shall be equal to 2.     -   The variables MinQtLog2SizeY, MinQtLog2SizeC, MinQtSizeY,         MinQtSizeC, MaxBtSizeY, MaxBtSizeC, MinBtSizeY, MaxTtSizeY,         MaxTtSizeC, MinTtSizeY, MaxMttDepthY and MaxMttDepthC are         derived as follows:

MinQtSizeY=1<<MinQtLog2SizeY

MinQtSizeC=1<<MinQtLog2SizeC

MinBtSizeY=1<<MinCbLog2SizeY

MinTtSizeY=1<<MinCbLog2SizeY

-   -   If slice_type equal to 2 (I),

MinQtLog2SizeY=MinCbLog2SizeY+pic_log2_diff_min_qt_min_cb_intra_slice_luma

MinQtLog2SizeC=MinCbLog2SizeC+pic_log2_diff_min_qt_min_cb_intra_slice_chroma

MaxBtSizeY=1<<(MinQtLog2SizeY+pic_log2_diff_max_bt_min_qt_intra_slice_luma)

MaxBtSizeC=1<(MinQtLog2SizeC+pic_log2_diff_max_bt_min_qt_intra_slice_chroma)

MaxTtSizeY=1<<(MinQtLog2SizeY+pic_log2_diff_max_tt_min_qt_intra_slice_luma)

MaxTtSizeC=1<<(MinQtLog2SizeC+pic_log2_diff_max_tt_min_qt_intra_slice_chroma)

MaxMtDepthY=pic_max_mtt_hierarchy_depth_intra_slice_luma

MaxMttDepthC=pic_max_mtt_hierarchy_depth_intra_slice_chroma

CuQpDeltaSubdiv=pic_cu_qp_delta_subdiv_intra_slice

CuChromaQpOffsetSubdiv=pic_cu_chroma_qp_offset_subdiv_intra_slice

-   -   Otherwise (slice_type equal to 0 (B) or 1 (P)),

MinQtLog2SizeY=MinCbLog2SizeY+pic_log2_diff_min_qt_min_cb_inter_slice

MinQtLog2SizeC=MinCbLog2SizeC+pic_log2_diff_min_qt_min_cb_inter_slice

MaxBtSizeY=1<<(MinQtLog2SizeY+pic_log2_diff_max_bt_min_qt_inter_slice)

MaxBtSizeC=1<<(MinQtLog2SizeC+pic_log2_diff_max_bt_min_qt_inter_slice)

MaxTtSizeY=1<<(MinQtLog2SizeY+pic_log2_diff_max_tt_min_qt_inter_slice)

MaxTtSizeC=1<<(MinQtLog2SizeC+pic_log2_diff_max_tt_min_qt_inter_slice)

MaxMttDepthY=pic_max_mtt_hierarchy_depth_inter_slice

MaxMttDepthC=pic_max_mtt_hierarchy_depth_inter_slice

CuQpDeltaSubdiv=pic_cu_qp_delta_subdiv_inter_slice

CuChromaQpOffsetSubdiv=pic_cu_chroma_qp_offset_subdiv_inter_slice

-   -   slice_rpl_sps_flag[i] equal to 1 specifies that reference         picture list i of the current slice is derived based on one of         the ref_pic_list_struct(listIdx, rplsIdx) syntax structures with         listIdx equal to i in the SPS. slice_rpl_sps_flag[i] equal to 0         specifies that reference picture list i of the current slice is         derived based on the ref_pic_list_struct(listIdx, rplsIdx)         syntax structure with listIdx equal to i that is directly         included in the slice headers of the current picture.     -   When slice_rpl_sps_flag[i] is not present, the following         applies:         -   If pic_rpl_present_flag is equal to 1, the value of             slice_rpl_sps_flag[i] is inferred to be equal to             pic_rpl_sps_flag[i].         -   Otherwise, if num_ref_pic_lists_in_sps[i] is equal to 0, the             value of ref_pic_list_sps_flag[i] is inferred to be equal to             0.         -   Otherwise, if num_ref_pic_lists_in_sps[i] is greater than 0             and if rpl1_idx_present_flag is equal to 0, the value of             slice_rpl_sps_flag[1] is inferred to be equal to             slice_rpl_sps_flag[0].     -   slice_rpl_idx[i] specifies the index, into the list of the         ref_pic_list_struct(listIdx, rplsIdx) syntax structures with         listIdx equal to i included in the SPS, of the         ref_pic_list_struct(listIdx, rplsIdx) syntax structure with         listIdx equal to i that is used for derivation of reference         picture list i of the current picture. The syntax element         slice_rpl_idx[i] is represented by         Ceil(Log2(num_ref_pic_lists_in_sps[i])) bits. When not present,         the value of slice_rpl_idx[i] is inferred to be equal to 0. The         value of slice_rpl_idx[i] shall be in the range of 0 to         num_ref_pic_lists_in_sps[i]−1, inclusive. When         slice_rpl_sps_flag[i] is equal to 1 and         num_ref_pic_lists_in_sps[i] is equal to 1, the value of         slice_rpl_idx[i] is inferred to be equal to 0. When         slice_rpl_sps_flag[i] is equal to 1 and rpl1_idx_present_flag is         equal to 0, the value of slice_rpl_idx[1] is inferred to be         equal to slice_rpl_idx[0].     -   The variable RplsIdx[i] is derived as follows:

if( pic_rpl_present_flag )  RplsIdx[ i ] = PicRplsIdx[ i ] else  RplsIdx[ i ] = slice_rpl_sps_flag[ i ] ? slice_  rpl_idx[ i ] : num_ref_pic_lists_in_sps[ i ]

-   -   slice_poc_lsb_lt[i][j] specifies the value of the picture order         count modulo MaxPicOrderCntLsb of the j-th LTRP entry in the         i-th reference picture list. The length of the         slice_poc_lsb_lt[i][j] syntax element is         log2_max_pic_order_cnt_lsb_minus4+4 bits.     -   The variable PocLsbLt[i][j] is derived as follows:

  if( pic_rpl_present_flag )  PocLsbLt[ i ][ j ] = PocLsbLt[ i ][ j ] else  PocLsbLt[ i ][ j ] = ltrp_in_slice_header_flag[ i ][ RplsIdx[ i ] ] ?   slice_poc_lsb_lt[ i ][ j ] : rpls_poc_lsb_lt[ listIdx ][ RplsIdx [ i ] ][ j ]

-   -   slice_delta_poc_msb_present_flag[i][j] equal to 1 specifies that         slice_delta_poc_msb_cycle_lt[i][j] is present.         slice_delta_poc_msb_present_flag[i][j] equal to 0 specifies that         slice_delta_poc_msb_cycle_lt[i][j] is not present.     -   Let prevTid0Pic be the previous picture in decoding order that         has nuh_layer_id the same as the current picture, has TemporalId         equal to 0, and is not a RASL or RADL picture. Let         setOfPrevPocVals be a set consisting of the following:         -   the PicOrderCntVal of prevTid0Pic,         -   the PicOrderCntVal of each picture that is referred to by             entries in RefPicList[0] or RefPicList[1] of prevTid0Pic and             has nuh_layer_id the same as the current picture,         -   the PicOrderCntVal of each picture that follows prevTid0Pic             in decoding order, has nuh_layer_id the same as the current             picture, and precedes the current picture in decoding order.     -   When pic_rpl_present_flag is equal to 0 and there is more than         one value in setOfPrevPocVals for which the value modulo         MaxPicOrderCntLsb is equal to PocLsbLt[i][j], the value of         slice_delta_poc_msb_present_flag[i][i] shall be equal to 1.     -   slice_delta_poc_msb_cycle_lt[i][j] specifies the value of the         variable FullPocLt[i][j] as follows:

  if( pic_rpl_present_flag )  FullPocLt[ i ][ j ] = PicFullPocLt[ i ][ j ] else {  if( j = = 0 )   DeltaPocMsbCycleLt[ i ][ j ] = delta_poc_msb_cycle_lt[ i ][ j ]  else   DeltaPocMsbCycleLt[ i ][ j ] = delta_poc_msb_cycle_lt[ i ][ j ] + DeltaPocMsbCycleLt[ i ][ j − l ]  FullPocLt[ i ][ j ] = PicOrderCntVal −   DeltaPocMsbCycleLt[ i ][ j ] * MaxPicOrderCntLsb −  ( PicOrderCntVal & ( MaxPicOrderCntLsb − 1 ) ) + PocLsbLt[ i ][ j ] }

-   -   The value of slice_delta_poc_msb_cycle_lt[i][j] shall be in the         range of 0 to 2^((32-log2_max_pic_order_cnt_lsb_minus4-4)),         inclusive. When not present, the value of         slice_delta_poc_msb_cycle_lt[i][j] is inferred to be equal to 0.     -   num_ref_idx_active_override_flag equal to 1 specifies that the         syntax element num_ref_idx_active_minus1[0] is present for P and         B slices and that the syntax element         num_ref_idx_active_minus1[1] is present for B slices.         num_ref_idx_active_override_flag equal to 0 specifies that the         syntax elements num_ref_idx_active_minus1[0] and         num_ref_idx_active_minus1[1] are not present. When not present,         the value of num_ref_idx_active_override_flag is inferred to be         equal to 1.     -   num_ref_idx_active_minus1[i] is used for the derivation of the         variable NumRefIdxActive[i] as specified by Equation 7-122. The         value of num_ref_idx_active_minus1[i] shall be in the range of 0         to 14, inclusive.     -   For i equal to 0 or 1, when the current slice is a B slice,         num_ref_idx_active_override_flag is equal to 1, and         num_ref_idx_active_minus1[i] is not present,         num_ref_idx_active_minus1[i] is inferred to be equal to 0.     -   When the current slice is a P slice,         num_ref_idx_active_override_flag is equal to 1, and         num_ref_idx_active_minus1[0] is not present,         num_ref_idx_active_minus1[0] is inferred to be equal to 0.     -   The variable NumRefIdxActive[i] is derived as follows:

  for( i = 0; i < 2; i++ ) {  if( slice_type = = B || ( slice_type = = P && i = = 0 ) ) {   if( num_ref_idx_active_override_flag )    NumRefIdxActive[ i ] = num_ref_idx_active_minus1[ i ] + 1   else {    if( num_ref_entries[ i ][ RplsIdx[ i ] ] >= num_ref_idx_default_active_minus1[ i ] + 1 )     NumRefIdxActive[ i ] = num_ref_idx_     default_active_minus1[ i ] + 1    else     NumRefIdxActive[ i ] = num_ref_entries[ i ][ RplsIdx[ i ] ]   }  } else // slice_type = = I || ( slice_type = = P && i = = 1 )   NumRefIdxActive[ i ] = 0 }

-   -   The value of NumRefIdxActive[i]−1 specifies the maximum         reference index for reference picture list i that may be used to         decode the slice. When the value of NumRefIdxActive[i] is equal         to 0, no reference index for reference picture list i may be         used to decode the slice. When the current slice is a P slice,         the value of NumRefIdxActive[0] shall be greater than 0. When         the current slice is a B slice, both NumRefIdxActive[0] and         NumRefIdxActive[1] shall be greater than 0.     -   cabac_init_flag specifies the method for determining the         initialization table used in the initialization process for         context variables. When cabac_init_flag is not present, it is         inferred to be equal to 0.     -   collocated_from_l0_flag equal to 1 specifies that the collocated         picture used for temporal motion vector prediction is derived         from reference picture list 0. collocated_from_l0_flag equal to         0 specifies that the collocated picture used for temporal motion         vector prediction is derived from reference picture list 1.     -   When collocated_from_l0_flag is not present, the following         applies:         -   If slice_type is not equal to B, the value of             collocated_from_l0_flag is inferred to be equal to 1.         -   Otherwise (slice type is equal to B), the value of             collocated_from_l0_flag is inferred to be equal to             pps_collocated_from_l0_idc−1.     -   collocated_ref_idx specifies the reference index of the         collocated picture used for temporal motion vector prediction.     -   When slice_type is equal to P or when slice_type is equal to B         and collocated_from_l0_flag is equal to 1, collocated_ref_idx         refers to a picture in list 0, and the value of         collocated_ref_idx shall be in the range of 0 to         NumRefIdxActive[0]−1, inclusive.     -   When slice_type is equal to B and collocated_from_l0_flag is         equal to 0, collocated_ref_idx refers to a picture in list 1,         and the value of collocated_ref_idx shall be in the range of 0         to NumRefIdxActive[1]−1, inclusive.     -   When collocated_ref_idx is not present, the value of         collocated_ref_idx is inferred to be equal to 0.     -   It is a requirement of bitstream conformance that the picture         referred to by collocated_ref_idx shall be the same for all         slices of a coded picture.     -   It is a requirement of bitstream conformance that the         resolutions of the reference picture referred to by         collocated_ref_idx and the current picture shall be the same and         RefPicIsScaled[collocated_from_l0_flag? 0:1][collocated_ref_idx]         shall be equal to 0.     -   slice_qp_delta specifies the initial value of Qp_(Y) to be used         for the coding blocks in the slice until modified by the value         of CuQpDeltaVal in the coding unit layer. The initial value of         the Qp_(Y) quantization parameter for the slice, SliceQp_(Y), is         derived as follows:

SliceQp_(Y)=26+init_qp_minus26+slice_qp_delta

-   -   The value of SliceQp_(Y) shall be in the range of −QpBdOffset to         +63, inclusive.     -   slice_cb_qp_offset specifies a difference to be added to the         value of pps_cb_qp_offset when determining the value of the         Qp′_(Cb) quantization parameter. The value of slice_cb_qp_offset         shall be in the range of −12 to +12, inclusive. When         slice_cb_qp_offset is not present, it is inferred to be equal         to 0. The value of pps_cb_qp_offset+slice_cb_qp_offset shall be         in the range of −12 to +12, inclusive.     -   slice_cr_qp_offset specifies a difference to be added to the         value of pps_cr_qp_offset when determining the value of the         Qp′_(Cr) quantization parameter. The value of slice_cr_qp_offset         shall be in the range of −12 to +12, inclusive. When         slice_cr_qp_offset is not present, it is inferred to be equal         to 0. The value of pps_cr_qp_offset+slice_cr_qp_offset shall be         in the range of −12 to +12, inclusive.     -   slice_joint_cbcr_qp_offset specifies a difference to be added to         the value of pps_joint_cbcr_qp_offset_value when determining the         value of the Qp′_(CbCr). The value of slice_joint_cbcr_qp_offset         shall be in the range of −12 to +12, inclusive. When         slice_joint_cbcr_qp_offset is not present, it is inferred to be         equal to 0. The value of         pps_joint_cbcr_qp_offset_value+slice_joint_cbcr_qp_offset shall         be in the range of −12 to +12, inclusive.     -   slice_sao_luma_flag equal to 1 specifies that SAO is enabled for         the luma component in the current slice; slice_sao_luma_flag         equal to 0 specifies that SAO is disabled for the luma component         in the current slice. When slice_sao_luma_flag is not present,         it is inferred to be equal to pic_sao_luma_enabled_flag.     -   slice_sao_chroma_flag flag equal to 1 specifies that SAO is         enabled for the chroma component in the current slice;         slice_sao_chroma_flag equal to 0 specifies that SAO is disabled         for the chroma component in the current slice. When         slice_sao_chroma_flag is not present, it is inferred to be equal         to pic_sao_chroma_enabled_flag.     -   slice_alf_enabled_flag equal to 1 specifies that adaptive loop         filter is enabled and may be applied to Y, Cb, or Cr colour         component in a slice. slice_alf_enabled_flag equal to 0         specifies that adaptive loop filter is disabled for all colour         components in a slice. When not present, the value of         slice_alf_enabled_flag is inferred to be equal to         pic_alf_enabled_flag.     -   slice_num_alf_aps_ids_luma specifies the number of ALF APSs that         the slice refers to. When slice_alf_enabled_flag is equal to 1         and slice_num_alf_aps_ids_luma is not present, the value of         slice_num_alf_aps_ids_luma is inferred to be equal to the value         of pic_num_alf_aps_ids_luma.     -   slice_alf_aps_id_luma[i] specifies the         adaptation_parameter_set_id of the i-th ALF APS that the luma         component of the slice refers to. The TemporalId of the APS NAL         unit having aps_params_type equal to ALF_APS and         adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i]         shall be less than or equal to the TemporalId of the coded slice         NAL unit. When slice_alf_enabled_flag is equal to 1 and         slice_alf_aps_id_luma[i] is not present, the value of         slice_alf_aps_id_luma[i] is inferred to be equal to the value of         pic_alf_aps_id_luma[i].     -   The value of alf_luma_filter_signal_flag of the APS NAL unit         having aps_params_type equal to ALF_APS and         adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i]         shall be equal to 1.     -   slice_alf_chroma_idc equal to 0 specifies that the adaptive loop         filter is not applied to Cb and Cr colour components.         slice_alf_chroma_idc equal to 1 indicates that the adaptive loop         filter is applied to the Cb colour component.         slice_alf_chroma_idc equal to 2 indicates that the adaptive loop         filter is applied to the Cr colour component.         slice_alf_chroma_idc equal to 3 indicates that the adaptive loop         filter is applied to Cb and Cr colour components. When         slice_alf_chroma_idc is not present, it is inferred to be equal         to pic_alf_chroma_idc.     -   slice_alf_aps_id_chroma specifies the         adaptation_parameter_set_id of the ALF APS that the chroma         component of the slice refers to. The TemporalId of the APS NAL         unit having aps_params_type equal to ALF_APS and         adaptation_parameter_set_id equal to slice_alf_aps_id_chroma         shall be less than or equal to the TemporalId of the coded slice         NAL unit. When slice_alf_enabled_flag is equal to 1 and         slice_alf_aps_id_chroma is not present, the value of         slice_alf_aps_id_chroma is inferred to be equal to the value of         pic_alf_aps_id_chroma. The value of         alf_chroma_filter_signal_flag of the APS NAL unit having         aps_params_type equal to ALF_APS and adaptation_parameter_set_id         equal to slice_alf_aps_id_chroma shall be equal to 1.     -   slice_deblocking_filter_override_flag equal to 1 specifies that         deblocking parameters are present in the slice header.         slice_deblocking_filter_override_flag equal to 0 specifies that         deblocking parameters are not present in the slice header. When         not present, the value of slice_deblocking_filter_override_flag         is inferred to be equal to pic_deblocking_filter_override_flag.     -   slice_deblocking_filter_disabled_flag equal to 1 specifies that         the operation of the deblocking filter is not applied for the         current slice. slice_deblocking_filter_disabled_flag equal to 0         specifies that the operation of the deblocking filter is applied         for the current slice. When         slice_deblocking_filter_disabled_flag is not present, it is         inferred to be equal to pic_deblocking_filter_disabled_flag.     -   slice_beta_offset_div2 and slice_tc_offset_div2 specify the         deblocking parameter offsets for ß and tC (divided by 2) for the         current slice. The values of slice_beta_offset_div2 and         slice_tc_offset_div2 shall both be in the range of −6 to 6,         inclusive. When not present, the values of         slice_beta_offset_div2 and slice_tc_offset_div2 are inferred to         be equal to pic_beta_offset_div2 and pic_tc_offset_div2,         respectively.     -   When entry_point_offsets_present_flag is equal to 1, the         variable NumEntryPoints, which specifies the number of entry         points in the current slice, is derived as follows:

  NumEntryPoints = 0 for( i = 1; i < NumCtuInCurrSlice; i++ ) {  CtbAddrInRs = CtbAddrInCurrSlice[ i ]  CtbAddrX = ( CtbAddrInRs % PicWidthInCtbsY )  CtbAddrY = ( CtbAddrInRs / PicWidthInCtbsY )  if( CtbAddrX = = CtbToTileColBd[ CtbAddrX ] &&   ( CtbAddrY = = CtbToTileRowBd[ CtbAddrY ] ||    entropy_coding_sync_enabled_flag ) )   NumEntryPoints++ }

-   -   offset_len_minus1 plus 1 specifies the length, in bits, of the         entry_point_offset_minus1[i] syntax elements. The value of         offset_len_minus1 shall be in the range of 0 to 31, inclusive.     -   entry_point_offset_minus1[i] plus 1 specifies the i-th entry         point offset in bytes, and is represented by offset_len_minus1         plus 1 bits. The slice data that follow the slice header         consists of NumEntryPoints+1 subsets, with subset index values         ranging from 0 to NumEntryPoints, inclusive. The first byte of         the slice data is considered byte 0. When present, emulation         prevention bytes that appear in the slice data portion of the         coded slice NAL unit are counted as part of the slice data for         purposes of subset identification. Subset 0 consists of bytes 0         to entry_point_offset_minus1[0], inclusive, of the coded slice         data, subset k, with k in the range of 1 to NumEntryPoints−1,         inclusive, consists of bytes firstByte[k] to lastByte[k],         inclusive, of the coded slice data with firstByte[k] and         lastByte[k] defined as:

firstByte[k]=Σ_(n=1) ^(k)(entry_point_offset_minus1[n−1]+1)

lastByte[k]=firstByte[k]+entry_point_offset_minus1[k]

-   -   The last subset (with subset index equal to NumEntryPoints)         consists of the remaining bytes of the coded slice data.     -   When entropy_coding_sync_enabled_flag is equal to 0 and the         slice contains one or more complete tiles, each subset shall         consist of all coded bits of all CTUs in the slice that are         within the same tile, and the number of subsets (i.e., the value         of NumEntryPoints+1) shall be equal to the number of tiles in         the slice.     -   When entropy_coding_sync_enabled_flag is equal to 0 and the         slice contains a subset of CTU rows from a single tile, the         NumEntryPoints shall be 0, and the number of subsets shall be 1.         The subset shall consist of all coded bits of all CTUs in the         slice.     -   When entropy_coding_sync_enabled_flag is equal to 1, each subset         k with k in the range of 0 to NumEntryPoints, inclusive, shall         consist of all coded bits of all CTUs in a CTU row within a         tile, and the number of subsets (i.e., the value of         NumEntryPoints+1) shall be equal to the total number of         tile-specific CTU rows in the slice.     -   slice_header_extension_length specifies the length of the slice         header extension data in bytes, not including the bits used for         signalling slice_header_extension_length itself. The value of         slice_header_extension_length shall be in the range of 0 to 256,         inclusive. When not present, the value of         slice_header_extension_length is inferred to be equal to 0.     -   slice_header_extension_data_byte[i] may have any value. Decoders         conforming to this version of this Specification shall ignore         the values of all the slice_header_extension_data_byte[i] syntax         elements. Its value does not affect decoder conformance to         profiles specified in this version of specification.

As provided above with respect to Table 2, the sequence parameter set syntax structure provided in JVET-P2001 includes syntax elements specifying the position of subpictures in a picture. The signaling provided in JVET-P2001 for signaling subpictures may be less than ideal. For example, in some cases the signaling in JVET-P2001 explicitly signals values which may be inferred, which is inefficient.

FIG. 1 is a block diagram illustrating an example of a system that may be configured to code (i.e., encode and/or decode) video data according to one or more techniques of this disclosure. System 100 represents an example of a system that may encapsulate video data according to one or more techniques of this disclosure. As illustrated in FIG. 1 , system 100 includes source device 102, communications medium 110, and destination device 120. In the example illustrated in FIG. 1 , source device 102 may include any device configured to encode video data and transmit encoded video data to communications medium 110. Destination device 120 may include any device configured to receive encoded video data via communications medium 110 and to decode encoded video data. Source device 102 and/or destination device 120 may include computing devices equipped for wired and/or wireless communications and may include, for example, set top boxes, digital video recorders, televisions, desktop, laptop or tablet computers, gaming consoles, medical imagining devices, and mobile devices, including, for example, smartphones, cellular telephones, personal gaming devices.

Communications medium 110 may include any combination of wireless and wired communication media, and/or storage devices. Communications medium 110 may include coaxial cables, fiber optic cables, twisted pair cables, wireless transmitters and receivers, routers, switches, repeaters, base stations, or any other equipment that may be useful to facilitate communications between various devices and sites. Communications medium 110 may include one or more networks. For example, communications medium 110 may include a network configured to enable access to the World Wide Web, for example, the Internet. A network may operate according to a combination of one or more telecommunication protocols. Telecommunications protocols may include proprietary aspects and/or may include standardized telecommunication protocols. Examples of standardized telecommunications protocols include Digital Video Broadcasting (DVB) standards, Advanced Television Systems Committee (ATSC) standards, Integrated Services Digital Broadcasting (ISDB) standards, Data Over Cable Service Interface Specification (DOCSIS) standards, Global System Mobile Communications (GSM) standards, code division multiple access (CDMA) standards, 3rd Generation Partnership Project (3GPP) standards, European Telecommunications Standards Institute (ETSI) standards, Internet Protocol (IP) standards, Wireless Application Protocol (WAP) standards, and Institute of Electrical and Electronics Engineers (IEEE) standards.

Storage devices may include any type of device or storage medium capable of storing data. A storage medium may include a tangible or non-transitory computer-readable media. A computer readable medium may include optical discs, flash memory, magnetic memory, or any other suitable digital storage media. In some examples, a memory device or portions thereof may be described as non-volatile memory and in other examples portions of memory devices may be described as volatile memory. Examples of volatile memories may include random access memories (RAM), dynamic random access memories (DRAM), and static random access memories (SRAM). Examples of non-volatile memories may include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. Storage device(s) may include memory cards (e.g., a Secure Digital (SD) memory card), internal/external hard disk drives, and/or internal/external solid state drives. Data may be stored on a storage device according to a defined file format.

FIG. 4 is a conceptual drawing illustrating an example of components that may be included in an implementation of system 100. In the example implementation illustrated in FIG. 4 , system 100 includes one or more computing devices 402A-402N, television service network 404, television service provider site 406, wide area network 408, local area network 410, and one or more content provider sites 412A-412N. The implementation illustrated in FIG. 4 represents an example of a system that may be configured to allow digital media content, such as, for example, a movie, a live sporting event, etc., and data and applications and media presentations associated therewith to be distributed to and accessed by a plurality of computing devices, such as computing devices 402A-402N. In the example illustrated in FIG. 4 , computing devices 402A-402N may include any device configured to receive data from one or more of television service network 404, wide area network 408, and/or local area network 410. For example, computing devices 402A-402N may be equipped for wired and/or wireless communications and may be configured to receive services through one or more data channels and may include televisions, including so-called smart televisions, set top boxes, and digital video recorders. Further, computing devices 402A-402N may include desktop, laptop, or tablet computers, gaming consoles, mobile devices, including, for example, “smart” phones, cellular telephones, and personal gaming devices.

Television service network 404 is an example of a network configured to enable digital media content, which may include television services, to be distributed. For example, television service network 404 may include public over-the-air television networks, public or subscription-based satellite television service provider networks, and public or subscription-based cable television provider networks and/or over the top or Internet service providers. It should be noted that although in some examples television service network 404 may primarily be used to enable television services to be provided, television service network 404 may also enable other types of data and services to be provided according to any combination of the telecommunication protocols described herein. Further, it should be noted that in some examples, television service network 404 may enable two-way communications between television service provider site 406 and one or more of computing devices 402A-402N. Television service network 404 may comprise any combination of wireless and/or wired communication media. Television service network 404 may include coaxial cables, fiber optic cables, twisted pair cables, wireless transmitters and receivers, routers, switches, repeaters, base stations, or any other equipment that may be useful to facilitate communications between various devices and sites. Television service network 404 may operate according to a combination of one or more telecommunication protocols. Telecommunications protocols may include proprietary aspects and/or may include standardized telecommunication protocols. Examples of standardized telecommunications protocols include DVB standards, ATSC standards, ISDB standards, DTMB standards, DMB standards, Data Over Cable Service Interface Specification (DOCSIS) standards, HbbTV standards, W3C standards, and UPnP standards.

Referring again to FIG. 4 , television service provider site 406 may be configured to distribute television service via television service network 404. For example, television service provider site 406 may include one or more broadcast stations, a cable television provider, or a satellite television provider, or an Internet-based television provider. For example, television service provider site 406 may be configured to receive a transmission including television programming through a satellite uplink/downlink. Further, as illustrated in FIG. 4 , television service provider site 406 may be in communication with wide area network 408 and may be configured to receive data from content provider sites 412A-412N. It should be noted that in some examples, television service provider site 406 may include a television studio and content may originate therefrom.

Wide area network 408 may include a packet based network and operate according to a combination of one or more telecommunication protocols. Telecommunications protocols may include proprietary aspects and/or may include standardized telecommunication protocols. Examples of standardized telecommunications protocols include Global System Mobile Communications (GSM) standards, code division multiple access (CDMA) standards, 3^(rd) Generation Partnership Project (3GPP) standards, European Telecommunications Standards Institute (ETSI) standards, European standards (EN), IP standards, Wireless Application Protocol (WAP) standards, and Institute of Electrical and Electronics Engineers (IEEE) standards, such as, for example, one or more of the IEEE 802 standards (e.g., Wi-Fi). Wide area network 408 may comprise any combination of wireless and/or wired communication media. Wide area network 408 may include coaxial cables, fiber optic cables, twisted pair cables, Ethernet cables, wireless transmitters and receivers, routers, switches, repeaters, base stations, or any other equipment that may be useful to facilitate communications between various devices and sites. In one example, wide area network 408 may include the Internet. Local area network 410 may include a packet based network and operate according to a combination of one or more telecommunication protocols. Local area network 410 may be distinguished from wide area network 408 based on levels of access and/or physical infrastructure. For example, local area network 410 may include a secure home network.

Referring again to FIG. 4 , content provider sites 412A-412N represent examples of sites that may provide multimedia content to television service provider site 406 and/or computing devices 402A-402N. For example, a content provider site may include a studio having one or more studio content servers configured to provide multimedia files and/or streams to television service provider site 406. In one example, content provider sites 412A-412N may be configured to provide multimedia content using the IP suite. For example, a content provider site may be configured to provide multimedia content to a receiver device according to Real Time Streaming Protocol (RTSP), HTTP, or the like. Further, content provider sites 412A-412N may be configured to provide data, including hypertext based content, and the like, to one or more of receiver devices computing devices 402A-402N and/or television service provider site 406 through wide area network 408. Content provider sites 412A-412N may include one or more web servers. Data provided by data provider site 412A-412N may be defined according to data formats.

Referring again to FIG. 1 , source device 102 includes video source 104, video encoder 106, data encapsulator 107, and interface 108. Video source 104 may include any device configured to capture and/or store video data. For example, video source 104 may include a video camera and a storage device operably coupled thereto. Video encoder 106 may include any device configured to receive video data and generate a compliant bitstream representing the video data. A compliant bitstream may refer to a bitstream that a video decoder can receive and reproduce video data therefrom. Aspects of a compliant bitstream may be defined according to a video coding standard. When generating a compliant bitstream video encoder 106 may compress video data. Compression may be lossy (discernible or indiscernible to a viewer) or lossless. FIG. 5 is a block diagram illustrating an example of video encoder 500 that may implement the techniques for encoding video data described herein. It should be noted that although example video encoder 500 is illustrated as having distinct functional blocks, such an illustration is for descriptive purposes and does not limit video encoder 500 and/or sub-components thereof to a particular hardware or software architecture. Functions of video encoder 500 may be realized using any combination of hardware, firmware, and/or software implementations.

Video encoder 500 may perform intra prediction coding and inter prediction coding of picture areas, and, as such, may be referred to as a hybrid video encoder. In the example illustrated in FIG. 5 , video encoder 500 receives source video blocks. In some examples, source video blocks may include areas of picture that has been divided according to a coding structure. For example, source video data may include macroblocks, CTUs, CBs, sub-divisions thereof, and/or another equivalent coding unit. In some examples, video encoder 500 may be configured to perform additional sub-divisions of source video blocks. It should be noted that the techniques described herein are generally applicable to video coding, regardless of how source video data is partitioned prior to and/or during encoding. In the example illustrated in FIG. 5 , video encoder 500 includes summer 502, transform coefficient generator 504, coefficient quantization unit 506, inverse quantization and transform coefficient processing unit 508, summer 510, intra prediction processing unit 512, inter prediction processing unit 514, filter unit 516, and entropy encoding unit 518. As illustrated in FIG. 5 , video encoder 500 receives source video blocks and outputs a bitstream.

In the example illustrated in FIG. 5 , video encoder 500 may generate residual data by subtracting a predictive video block from a source video block. The selection of a predictive video block is described in detail below. Summer 502 represents a component configured to perform this subtraction operation. In one example, the subtraction of video blocks occurs in the pixel domain. Transform coefficient generator 504 applies a transform, such as a discrete cosine transform (DCT), a discrete sine transform (DST), or a conceptually similar transform, to the residual block or sub-divisions thereof (e.g., four 8×8 transforms may be applied to a 16×16 array of residual values) to produce a set of residual transform coefficients. Transform coefficient generator 504 may be configured to perform any and all combinations of the transforms included in the family of discrete trigonometric transforms, including approximations thereof. Transform coefficient generator 504 may output transform coefficients to coefficient quantization unit 506. Coefficient quantization unit 506 may be configured to perform quantization of the transform coefficients. The quantization process may reduce the bit depth associated with some or all of the coefficients. The degree of quantization may alter the rate-distortion (i.e., bit-rate vs. quality of video) of encoded video data. The degree of quantization may be modified by adjusting a quantization parameter (QP). A quantization parameter may be determined based on slice level values and/or CU level values (e.g., CU delta QP values). QP data may include any data used to determine a QP for quantizing a particular set of transform coefficients. As illustrated in FIG. 5 , quantized transform coefficients (which may be referred to as level values) are output to inverse quantization and transform coefficient processing unit 508. Inverse quantization and transform coefficient processing unit 508 may be configured to apply an inverse quantization and an inverse transformation to generate reconstructed residual data. As illustrated in FIG. 5 , at summer 510, reconstructed residual data may be added to a predictive video block. In this manner, an encoded video block may be reconstructed and the resulting reconstructed video block may be used to evaluate the encoding quality for a given prediction, transformation, and/or quantization. Video encoder 500 may be configured to perform multiple coding passes (e.g., perform encoding while varying one or more of a prediction, transformation parameters, and quantization parameters). The rate-distortion of a bitstream or other system parameters may be optimized based on evaluation of reconstructed video blocks. Further, reconstructed video blocks may be stored and used as reference for predicting subsequent blocks.

Referring again to FIG. 5 , intra prediction processing unit 512 may be configured to select an intra prediction mode for a video block to be coded. Intra prediction processing unit 512 may be configured to evaluate a frame and determine an intra prediction mode to use to encode a current block. As described above, possible intra prediction modes may include planar prediction modes, DC prediction modes, and angular prediction modes. Further, it should be noted that in some examples, a prediction mode for a chroma component may be inferred from a prediction mode for a luma prediction mode. Intra prediction processing unit 512 may select an intra prediction mode after performing one or more coding passes. Further, in one example, intra prediction processing unit 512 may select a prediction mode based on a rate-distortion analysis. As illustrated in FIG. 5 , intra prediction processing unit 512 outputs intra prediction data (e.g., syntax elements) to entropy encoding unit 518 and transform coefficient generator 504. As described above, a transform performed on residual data may be mode dependent (e.g., a secondary transform matrix may be determined based on a prediction mode).

Referring again to FIG. 5 , inter prediction processing unit 514 may be configured to perform inter prediction coding for a current video block. Inter prediction processing unit 514 may be configured to receive source video blocks and calculate a motion vector for PUs of a video block. A motion vector may indicate the displacement of a prediction unit of a video block within a current video frame relative to a predictive block within a reference frame. Inter prediction coding may use one or more reference pictures. Further, motion prediction may be uni-predictive (use one motion vector) or bi-predictive (use two motion vectors). Inter prediction processing unit 514 may be configured to select a predictive block by calculating a pixel difference determined by, for example, sum of absolute difference (SAD), sum of square difference (SSD), or other difference metrics. As described above, a motion vector may be determined and specified according to motion vector prediction. Inter prediction processing unit 514 may be configured to perform motion vector prediction, as described above. Inter prediction processing unit 514 may be configured to generate a predictive block using the motion prediction data. For example, inter prediction processing unit 514 may locate a predictive video block within a frame buffer (not shown in FIG. 5 ). It should be noted that inter prediction processing unit 514 may further be configured to apply one or more interpolation filters to a reconstructed residual block to calculate sub-integer pixel values for use in motion estimation. Inter prediction processing unit 514 may output motion prediction data for a calculated motion vector to entropy encoding unit 518.

Referring again to FIG. 5 , filter unit 516 receives reconstructed video blocks and coding parameters and outputs modified reconstructed video data. Filter unit 516 may be configured to perform deblocking and/or Sample Adaptive Offset (SAO) filtering. SAO filtering is a non-linear amplitude mapping that may be used to improve reconstruction by adding an offset to reconstructed video data. It should be noted that as illustrated in FIG. 5 , intra prediction processing unit 512 and inter prediction processing unit 514 may receive modified reconstructed video block via filter unit 216. Entropy encoding unit 518 receives quantized transform coefficients and predictive syntax data (i.e., intra prediction data and motion prediction data). It should be noted that in some examples, coefficient quantization unit 506 may perform a scan of a matrix including quantized transform coefficients before the coefficients are output to entropy encoding unit 518. In other examples, entropy encoding unit 518 may perform a scan. Entropy encoding unit 518 may be configured to perform entropy encoding according to one or more of the techniques described herein. In this manner, video encoder 500 represents an example of a device configured to generate encoded video data according to one or more techniques of this disclosure.

Referring again to FIG. 1 , data encapsulator 107 may receive encoded video data and generate a compliant bitstream, e.g., a sequence of NAL units according to a defined data structure. A device receiving a compliant bitstream can reproduce video data therefrom. Further, as described above, sub-bitstream extraction may refer to a process where a device receiving a ITU-T H.265 compliant bitstream forms a new ITU-T H.265 compliant bitstream by discarding and/or modifying data in the received bitstream. It should be noted that the term conforming bitstream may be used in place of the term compliant bitstream. In one example, data encapsulator 107 may be configured to generate syntax according to one or more techniques described herein. It should be noted that data encapsulator 107 need not necessary be located in the same physical device as video encoder 106. For example, functions described as being performed by video encoder 106 and data encapsulator 107 may be distributed among devices illustrated in FIG. 4 .

As described above, the signaling provided in JVET-P2001 for signaling subpictures may be less than ideal. In one example, according to the techniques herein, the horizontal position of the top left CTU of 0-th subpicture and vertical position of top left CTU of 0-th subpicture may not be signaled and instead inference may be used for these syntax elements. Since all the subpictures together encompass the whole picture, this requires that the top-left corner of the first subpicture is at the top-left corner of the picture. Table 8 illustrates an example of the relevant portion of a seq_parameter_set( ) syntax structure according to the techniques herein.

TABLE 8 Descriptor seq_parameter_set_rbsp( ) { ...  ref_pic_resampling_enabled_flag u(1)  pic_width_max_in_luma_samples ue(v)  pic_height_max_in_luma_samples ue(v)  sps_log2_ctu_size_minus5 u(2)  subpics_present_flag u(1)  if( subpics_present_flag ) {   sps_num_subpics_minus1 u(8)   for(i = 0; i <= sps_num_subpics_minus1; i++ ) {    if( i > 0 ) {      subpic_ctu_top_left_x[ i ] u(v)      subpic_ctu_top_left_y[ i ] u(v)    }    subpic_width_minus1[ i ] u(v)    subpic_height_minus1[ i ] u(v)    subpic_treated_as_pic_flag[ i ] u(1)    loop_filter_across_subpic_enabled_flag[ i ] u(1)   }  }  sps_subpic_id_present_flag u(1)  if( sps_subpic_id_present_flag ) {   sps_subpic_id_signalling_present_flag u(1)   if( sps_subpic_id_signalling_present_flag ) {    sps_subpic_id_len_minus1 ue(v)    for( i = 0; i <= sps_num_subpics_minus1; i++ )     sps_subpic_id[ i ] u(v)   }  }  ... ue(v) }

-   -   With respect to Table 8, the semantics may be based on the         semantics provided above, with the following example semantics         for syntax elements subpic_ctu_top_left_x[i] and         subpic_ctu_top_left_y[i]:     -   subpic_ctu_top_left_x[i] specifies horizontal position of top         left CTU of i-th subpicture in unit of CtbSizeY. The length of         the syntax element is         Ceil(Log2(pic_width_max_in_luma_samples/CtbSizeY)) bits. When         not present, the value of subpic_ctu_top_left_x[i] is inferred         to be equal to 0.     -   subpic_ctu_top_left_y[i] specifies vertical position of top left         CTU of i-th subpicture in unit of CtbSizeY. The length of the         syntax element is         Ceil(Log2(pic_height_max_in_luma_samples/CtbSizeY)) bits. When         not present, the value of subpic_ctu_top_left_y[i] is inferred         to be equal to 0.

In one example, according to the techniques herein, the width of the last subpicture, i.e. sps_num_subpics_minus1-th subpicture and height of the last subpicture, i.e. sps_num_subpics_minus1-th subpicture may not be signaled and instead an inference may be used for these syntax elements. Since all the subpictures together encompass the whole picture, this requires that the last subpicture bottom-right corner is at the bottom-right corner of the picture. Table 9 illustrates an example of the relevant portion of a seq_parameter_set( ) syntax structure according to the techniques herein.

TABLE 9 Descriptor seq_parameter_set_rbsp( ) { ...  ref_pic_resampling_enabled_flag u(1)  pic_width_max_in_luma_samples ue(v)  pic_height_max_in_luma_samples ue(v)  sps_log2_ctu_size_minus5 u(2)  subpics_present_flag u(1)  if( subpics_present_flag ) {   sps_num_subpics_minus1 u(8)   for( i = 0; i <= sps_num_subpics_minus1; i++ ) {    subpic_ctu_top_left_x[ i ] u(v)    subpic_ctu_top_left_y[ i ] u(v)    if( i < sps_num_subpics_minus1 ) {      subpic_width_minus1[ i ] u(v)      subpic_height_minus1[ i ] u(v)    }    subpic_treated_as_pic_flag[ i ] u(1)    loop_filter_across_subpic_enabled_flag[ i ] u(1)   }  }  sps_subpic_id_present_flag u(1)  if( sps_subpic_id_present_flag ) {   sps_subpic_id_signalling_present_flag u(1)   if( sps_subpic_id_signalling_present_flag ) {    sps_subpic_id_len_minus1 ue(v)    for( i = 0; i <= sps_num_subpics_minus1; i++ )     sps_subpic_id[ i ] u(v)   }  }  ... ue(v) }

-   -   With respect to Table 9, the semantics may be based on the         semantics provided above, with the following example semantics         for syntax elements subpic_width_minus1[i] and         subpic_height_minus1[i]:     -   subpic_width_minus1[i] plus 1 specifies the width of the i-th         subpicture in units of CtbSizeY. The length of the syntax         element is Ceil(Log2(pic_width_max_in_luma_samples/CtbSizeY))         bits. When not present, the value of subpic_width_minus1[i] is         inferred to be equal to         Ceil(pic_width_max_in_luma_samples/CtbSizeY)−subpic_ctu_top_left_x[i]−1.     -   In a variant:     -   The length of this syntax element is Max(1,         Ceil(Log2(Ceil(pic_width_max_in_luma_samples/CtbSizeY)))) bits.     -   In a variant:     -   Log2(pic_width_max_in_luma_samples/CtbSizeY) above may be         changed to         Log2((pic_width_max_in_luma_samples+CtbSizeY−1)/CtbSizeY)     -   subpic_height_minus1[i] plus 1 specifies the height of the i-th         subpicture in units of CtbSizeY. The length of the syntax         element is Ceil(Log2(pic_height_max_in_luma_samples/CtbSizeY))         bits. When not present, the value of subpic_height_minus1[i] is         inferred to be equal to         Ceil(pic_height_max_in_luma_samples/CtbSizeY)−subpic_ctu_top_left_y[i]−1.     -   In a variant:     -   The length of the syntax element is Max(1,         Ceil(Log2(Ceil(pic_height_max_in_luma_samples/CtbSizeY)))) bits.     -   In a variant:     -   Log2(pic_height_max_in_luma_samples/CtbSizeY) may be changed to         Log2((pic_height_max_in_luma_samples+CtbSizeY−1)/CtbSizeY)     -   In another example, the semantics of subpic_width_minus1[i] and         subpic_height_minus1[i] may be based on the following:     -   subpic_width_minus1[i] plus 1 specifies the width of the i-th         subpicture in units of CtbSizeY. The length of the syntax         element is Ceil(Log2(pic_width_max_in_luma_samples/CtbSizeY))         bits. When not present and when subpics_present_flag is equal to         0, the value of subpic_width_minus1[i] is inferred to be equal         to Ceil(pic_width_max_in_luma_samples/CtbSizeY)−1. When not         present, and when subpics_present_flag is equal to 1, the value         of subpic_width_minus1[i] is inferred to be equal to         Ceil(pic_width_max_in_luma_samples/CtbSizeY)−subpic_ctu_top_left_x[i]−1.     -   subpic_height_minus1[i] plus 1 specifies the height of the i-th         subpicture in units of CtbSizeY. The length of the syntax         element is Ceil(Log2(pic_height_max_in_luma_samples/CtbSizeY))         bits. When not present and when subpics_present_flag is equal to         0, the value of subpic_height_minus1[i] is inferred to be equal         to Ceil(pic_height_max_in_luma_samples/CtbSizeY)−1. When not         present and when subpics_present_flag is equal to 1, the value         of subpic_height_minus1[i] is inferred to be equal to         Ceil(pic_height_max_in_luma_samples/CtbSizeY)−subpic_ctu_top_left_y[i]−1.     -   OR the following:     -   subpic_width_minus1[i] plus 1 specifies the width of the i-th         subpicture in units of CtbSizeY. The length of the syntax         element is Ceil(Log2(pic_width_max_in_luma_samples/CtbSizeY))         bits. When not present and when subpics_present_flag is equal to         0, the value of subpic_width_minus1[i] is inferred to be equal         to Ceil(pic_width_max_in_luma_samples/CtbSizeY)−1. When not         present, and when i is equal to sps_num_subpics_minus1, the         value of subpic_width_minus1[i] is inferred to be equal to         Ceil(pic_width_max_in_luma_samples/CtbSizeY)−subpic_ctu_top_left_x[i]−1.     -   subpic_height_minus1[i] plus 1 specifies the height of the i-th         subpicture in units of CtbSizeY. The length of the syntax         element is Ceil(Log2(pic_height_max_in_luma_samples/CtbSizeY))         bits. When not present and when subpics_present_flag is equal to         0, the value of subpic_height_minus1[i] is inferred to be equal         to Ceil(pic_height_max_in_luma_samples/CtbSizeY)−1. When not         present and when i is equal to sps_num_subpics_minus1, the value         of subpic_height_minus1[i] is inferred to be equal to         Ceil(pic_height_max_in_luma_samples/CtbSizeY)−subpic_ctu_top_left_y[i]−1.     -   In one example, according to the techniques herein, the         condition for the signaling of a subpicture identifier         (slice_subpic_id) of the subpicture that contains the slice in         the slice header may allow for the signaling of slice_subpic_id         when subpics_present_flag equal to 0. It should be noted that         under certain scenarios it is possible to signal         subpics_present_flag equal to 0 and still signal the subpicture         ID (in SPS or PPS or PH) which will require signaling the         slice_subpic_id in the slice header. This could for example         happen when an original bitstream had more than one subpicture         (each with a subpicture ID), whereas after the bitstream         extraction and merging operation a bitstream has only a single         subpicture with subpicture ID signalled for this subpicture.         Table 10 illustrates an example of the relevant portion of a         slice_header( ) syntax structure according to the techniques         herein.

TABLE 10 Descriptor slice_header( ) {  slice_pic_order_cnt_lsb u(v)  if( subpics_present_flag || sps_subpic_id_present_flag)   slice_subpic_id u(v)  if( rect_slice_flag || NumTilesInPic > 1 )   slice_address u(v)  if( !rect_slice_flag && NumTilesInPic > 1 )   num_tiles_in_slice_minus1 ue(v)  slice_type ue(v) ... }

-   -   With respect to Table 10, the semantics may be based on the         semantics provided above, with the following example semantics         for syntax elements slices_subpic_id:     -   slice_subpic_id specifies the subpicture identifier of the         subpicture that contains the slice. If slice_subpic_id is         present, the value of the variable SubPicIdx is derived to be         such that SubpicIdList[SubPicIdx] is equal to slice_subpic_id.         Otherwise (slice_subpic_id is not present), the variable         SubPicIdx is derived to be equal to 0. The length of         slice_subpic_id, in bits, is derived as follows:         -   If sps_subpic_id_signalling_present_flag is equal to 1, the             length of slice_subpic_id is equal to             sps_subpic_id_len_minus1+1.         -   Otherwise, if ph_subpic_id_signalling_present_flag is equal             to 1, the length of slice_subpic_id is equal to             ph_subpic_id_len_minus1+1.         -   Otherwise, if pps_subpic_id_signalling_present_flag is equal             to 1, the length of slice_subpic_id is equal to             pps_subpic_id_len_minus1+1.         -   Otherwise, the length of slice_subpic_id is equal to             Ceil(Log2 (sps_num_subpics_minus1+1))).     -   In a variant example:     -   When not present slice_subpic_id is inferred to be equal to 0.     -   In further examples, the condition for the inclusion of         slice_subpic_id in slice header could be modified from     -   if (subpics_present_flag∥sps_subpic_id_present_flag) to one of         the following:     -   if         (subpics_present_flag∥sps_subpic_id_signalling_present_flag∥ph_subpic_id_signalling_present_flag∥pps_subpic_id_signalling_present_flag)     -   OR     -   if         (subpics_present_flag∥sps_subpic_id_present_flag∥sps_subpic_id_signalling_present_flag∥ph_subpic_id_signalling_present_flag∥pps_subpic_id_signalling_present_flag)     -   OR     -   if         (sps_subpic_id_signalling_present_flag∥ph_subpic_id_signalling_present_flag∥pps_subpic_id_signalling_present_flag)     -   OR     -   if         (sps_subpic_id_present_flag∥sps_subpic_id_signalling_present_flag∥ph_subpic_id_signalling_present_flag∥pps_subpic_id_signalling_present_flag)

In general, according to the techniques herein, one or more of the sps_subpic_id_present_flag, sps_subpic_id_signalling_present_flag, ph_subpic_id_signalling_present_flag and pps_subpic_id_signalling_present_flag may be used in a logical OR (or some other logical operator) to determine whether slice_subpic_id is included in the slice header.

In a variant, the conditional signalling for slice_subpic_id in slice header may not use the subpics_present_flag. In one example this may be as illustrated in Table 10A:

TABLE 10A Descriptor slice_header( ) {  slice_pic_order_cnt_lsb u(v)  if(sps_subpic_id_present_flag)   slice_subpic_id u(v)  if( rect_slice_flag || NumTilesInPic > 1 )   slice_address u(v)  if( !rect_slice_flag && NumTilesInPic > 1 )   num_tiles_in_slice minus1 ue(v)  slice_type ue(v) ... }

In one example, alternatively (or additionally) to the examples described above, sps_subpic_id_present_flag and also ph_subpic_id_signalling_present_flag may be conditionally signaled based on the value of subpics_present_flag and the semantics of subpics_present_flag may be modified accordingly. Table 11 illustrates an example of the relevant portion of a seq_parameter_set( ) syntax structure according to the techniques herein.

TABLE 11 Descriptor seq_parameter_set_rbsp( ) { ...  ref_pic_resampling_enabled_flag u(1)  pic_width_max_in_luma_samples ue(v)  pic_height_max_in_luma_samples ue(v)  sps_log2_ctu_size_minus5 u(2)  subpics_present_flag u(1)  if( subpics_present_flag ) {   sps_num_subpics_minus1 u(8)   for( i = 0; i <= sps_num_subpics_minus1; i++ ) {    subpic_ctu_top_left_x[ i ] u(v)    subpic_ctu_top_left_y[ i ] u(v)    subpic_width_minus1[ i ] u(v)    subpic_height_minus1[ i ] u(v)    subpic_treated_as_pic_flag[ i ] u(1)    loop_filter_across_subpic_enabled_flag[ i ] u(1)   }  sps_subpic_id_present_flag u(1)  if( sps_subpic_id_present_flag ) {   sps_subpic_id_signalling_present_flag u(1)   if( sps_subpic_id_signalling_present_flag ) {    sps_subpic_id_len_minus1 ue(v)    for(i = 0; i <= sps_num_subpics_minus1; i++ )     sps_subpic_id[ i ] u(v)   }  }  }  ... ue(v) }

-   -   With respect to Table 11, the semantics may be based on the         semantics provided above, with the following example semantics         for syntax element subpics_present_flag:     -   subpics_present_flag equal to 1 specifies that subpicture         parameters are present in the SPS RBSP syntax and         slice_subpic_id is present in the slice header.         subpics_present_flag equal to 0 specifies that subpicture         parameters are not present in the SPS RBSP syntax and         slice_subpic_id is not present in the slice header.     -   When subpics_present_flag is equal to 0,         sps_subpic_id_signalling_present_flag shall be equal to 0.     -   When subpics_present_flag is equal to 0,         ph_subpic_id_signalling_present_flag shall be equal to 0.     -   When subpics_present_flag is equal to 0,         pps_subpic_id_signalling_present_flag shall be equal to 0.         -   NOTE—When a bitstream is the result of a sub-bitstream             extraction process and contains only a subset of the             subpictures of the input bitstream to the sub-bitstream             extraction process, it might be required to set the value of             subpics_present_flag equal to 1 in the RBSP of the SPSs.     -   In one example, the subpics_present_flag value can be used to         determine the presence of syntax element         ph_subpic_id_signalling_present_flag in picture_header_rbsp( )         as follows:

 if( sps_subpic_id_present_flag && !sps_subpic_id_signalling_present_flag && subpics_present_flag) {   ph_subpic_id_signalling_present_flag u(1)   if( ph_subpic_id_signalling_present_flag ) {    ph_subpic_id_len_minus1 ue(v)    for( i = 0; i <= sps_num_subpics_minus1; i++ )     ph_subpic_id[ i ] u(v)   }  }

It should be noted that in this case, the following constraint is not needed: When subpics_present_flag equal to 0, ph_subpic_id_signalling_present_flag shall be equal to 0.

Table 12 illustrates another example of the relevant portion of a seq_parameter_set( ) syntax structure where sps_subpic_id_present_flag is conditionally signaled based on the value of subpics_present_flag according to the techniques herein.

TABLE 12 Descriptor seq_parameter_set_rbsp( ) { ...  ref_pic_resamplmg_enabled_flag u(1)  pic_width_max_in_luma_samples ue(v)  pic_height_max_in_luma_samples ue(v)  sps_log2_ctu_size_minus5 u(2)  subpics_present_flag u(1)  if( subpics_present_flag ) {   sps_num_subpics_minus1 u(8)   for( i = 0; i <= sps_num_subpics_minus1; i++ ) {    subpic_ctu_top_left_x[ i ] u(v)    subpic_ctu_top_left_y[ i ] u(v)    subpic_width_minus1[ i ] u(v)    subpic_height_minus1[ i ] u(v)    subpic_treated_as_pic_flag[ i ] u(1)    loop_filter_across_subpic_enabled_flag[ i ] u(1)   }  }   if( subpics_present_flag )   sps_subpic_id_present_flag u(1)  if( sps_subpic_id_present_flag ) {   sps_subpic_id_signalling_present_flag u(1)   if( sps_subpic_id_signalling_present_flag ) {    sps_subpic_id_len_minus1 ue(v)    for( i = 0; i <= sps_num_subpics_minus1; i++ )     sps_subpic_id[ i ] u(v)   }  }  ... ue(v) }

-   -   With respect to Table 12, the semantics may be based on the         semantics provided above, with the following example semantics         for syntax element subpics_present_flag:     -   sps_subpic_id_present_flag equal to 1 specifies that subpicture         ID mapping is present in the SPS. sps_subpic_id_present_flag         equal to 0 specifies that subpicture ID mapping is not present         in the SPS.     -   When not present sps_subpic_id_present_flag is inferred to be         equal to 0.     -   It should be noted that in JVET-P2001, in the semantics for         syntax element sps_num_subpics_minus1, the value equal to 255 is         undefined. In one example, according to the techniques herein,         semantics for syntax element sps_num_subpics_minus1 may define a         value 255. For example, according to the techniques herein, the         semantics for syntax element sps_num_subpics_minus1 may be based         on the following:     -   sps_num_subpics_minus1 plus 1 specifies the number of         subpictures. sps_num_subpics_minus1 shall be in the range of 0         to 254. The value 255 is reserved. When not present, the value         of sps_num_subpics_minus1 is inferred to be equal to 0.     -   OR the following:     -   sps_num_subpics_minus1 plus 1 specifies the number of         subpictures. sps_num_subpics_minus1 shall be in the range of 0         to 255. When not present, the value of sps_num_subpics_minus1 is         inferred to be equal to 0.     -   It should be noted that keeping the value 256 for         sps_num_subpics_minus1 as reserved has the benefit of providing         future extensibility. For example, this special value could be         used later to allow support for defining more than 254         subpictures in a picture.     -   It should be noted that in JVET-P2001, there is a missing         conformance constraint related to sub-picture ID which may cause         the value of SubpicIdList[i] could be undefined under certain         conditions. That is, since sps_subpic_id_present_flag can be         signalled to be equal to 1 but each of the         sps_subpic_id_signalling_present_flag,         ph_subpic_id_signalling_present_flag and         pps_subpic_id_signalling_present_flag can be set to 0,         SubpicIdList[i] could be undefined under certain conditions. In         one example, according to the techniques herein the following         conformance constraint may be imposed:     -   When sps_subpic_id_present_flag is equal to 1, at least one of         sps_subpic_id_signalling_present_flag,         ph_subpic_id_signalling_present_flag and         pps_subpic_id_signalling_present_flag shall be equal to 1.     -   Alternatively, in one example, a conformance constraint may be         imposed based on the following semantics for         pps_subpic_id_signalling_present_flag and ph_subpic_id[i]:     -   pps_subpic_id_signalling_present_flag equal to 1 specifies that         subpicture ID mapping is signalled in the PPS.         pps_subpic_id_signalling_present_flag equal to 0 specifies that         subpicture ID mapping is not signalled in the PPS. When         sps_subpic_id_present_flag is 0 or         sps_subpic_id_signalling_present_flag is equal to 1,         pps_subpic_id_signalling_present_flag shall be equal to 0.     -   ph_subpic_id[i] specifies that subpicture ID of the i-th         subpicture. The length of the ph_subpic_id[i] syntax element is         ph_subpic_id_len_minus1+1 bits.     -   The list SubpicIdList[i] is derived as follows:     -   for (i=0; i<=sps_num_subpics_minus1; i++)

SubpicIdList[i]=sps_subpic_id_present_flag?(sps_subpic_id_signalling_present_flag? sps_subpic_id[i]: (ph_subpic_id_signalling_present_flag?ph_subpic_id[i]: pps_subpic_id[i])): i

-   -   When sps_subpic_id_present_flag is equal to 1 and         sps_subpic_id_signalling_present_flag is equal to 0, and         ph_subpic_id_signalling_present_flag is equal to 0,         pps_subpic_id_signalling_present_flag shall be equal to 1.

It should be noted that the above constraint can be written in other ways which require that every time two of the three flags (sps_subpic_id_signalling_present_flag, ph_subpic_id_signalling_present_flag and pps_subpic_id_signalling_present_flag) is equal to 0 the third remaining flag shall be equal to 1.

In this manner, source device 102 represents an example of a device configured to signal a syntax element indicating a number of subpictures in a picture and for each of the subpictures, other than the first subpicture, signal syntax elements indicating the position of the subpicture.

Referring again to FIG. 1 , interface 108 may include any device configured to receive data generated by data encapsulator 107 and transmit and/or store the data to a communications medium. Interface 108 may include a network interface card, such as an Ethernet card, and may include an optical transceiver, a radio frequency transceiver, or any other type of device that can send and/or receive information. Further, interface 108 may include a computer system interface that may enable a file to be stored on a storage device. For example, interface 108 may include a chipset supporting Peripheral Component Interconnect (PCI) and Peripheral Component Interconnect Express (PCIe) bus protocols, proprietary bus protocols, Universal Serial Bus (USB) protocols, PC, or any other logical and physical structure that may be used to interconnect peer devices.

Referring again to FIG. 1 , destination device 120 includes interface 122, data decapsulator 123, video decoder 124, and display 126. Interface 122 may include any device configured to receive data from a communications medium. Interface 122 may include a network interface card, such as an Ethernet card, and may include an optical transceiver, a radio frequency transceiver, or any other type of device that can receive and/or send information. Further, interface 122 may include a computer system interface enabling a compliant video bitstream to be retrieved from a storage device. For example, interface 122 may include a chipset supporting PCI and PCIe bus protocols, proprietary bus protocols, USB protocols, PC, or any other logical and physical structure that may be used to interconnect peer devices. Data decapsulator 123 may be configured to receive and parse any of the example syntax structures described herein.

Video decoder 124 may include any device configured to receive a bitstream (e.g., a sub-bitstream extraction) and/or acceptable variations thereof and reproduce video data therefrom. Display 126 may include any device configured to display video data. Display 126 may comprise one of a variety of display devices such as a liquid crystal display (LCD), a plasma display, an organic light emitting diode (OLED) display, or another type of display. Display 126 may include a High Definition display or an Ultra High Definition display. It should be noted that although in the example illustrated in FIG. 1 , video decoder 124 is described as outputting data to display 126, video decoder 124 may be configured to output video data to various types of devices and/or sub-components thereof. For example, video decoder 124 may be configured to output video data to any communication medium, as described herein.

FIG. 6 is a block diagram illustrating an example of a video decoder that may be configured to decode video data according to one or more techniques of this disclosure (e.g., the decoding process for reference-picture list construction described above). In one example, video decoder 600 may be configured to decode transform data and reconstruct residual data from transform coefficients based on decoded transform data. Video decoder 600 may be configured to perform intra prediction decoding and inter prediction decoding and, as such, may be referred to as a hybrid decoder. Video decoder 600 may be configured to parse any combination of the syntax elements described above in Tables 1-12. Video decoder 600 may decode a picture based on or according to the processes described above, and further based on parsed values in Tables 1-12.

In the example illustrated in FIG. 6 , video decoder 600 includes an entropy decoding unit 602, inverse quantization unit and transform coefficient processing unit 604, intra prediction processing unit 606, inter prediction processing unit 608, summer 610, post filter unit 612, and reference buffer 614. Video decoder 600 may be configured to decode video data in a manner consistent with a video coding system. It should be noted that although example video decoder 600 is illustrated as having distinct functional blocks, such an illustration is for descriptive purposes and does not limit video decoder 600 and/or sub-components thereof to a particular hardware or software architecture. Functions of video decoder 600 may be realized using any combination of hardware, firmware, and/or software implementations.

As illustrated in FIG. 6 , entropy decoding unit 602 receives an entropy encoded bitstream. Entropy decoding unit 602 may be configured to decode syntax elements and quantized coefficients from the bitstream according to a process reciprocal to an entropy encoding process. Entropy decoding unit 602 may be configured to perform entropy decoding according any of the entropy coding techniques described above. Entropy decoding unit 602 may determine values for syntax elements in an encoded bitstream in a manner consistent with a video coding standard. As illustrated in FIG. 6 , entropy decoding unit 602 may determine a quantization parameter, quantized coefficient values, transform data, and prediction data from a bitstream. In the example, illustrated in FIG. 6 , inverse quantization unit and transform coefficient processing unit 604 receives a quantization parameter, quantized coefficient values, transform data, and prediction data from entropy decoding unit 602 and outputs reconstructed residual data.

Referring again to FIG. 6 , reconstructed residual data may be provided to summer 610 Summer 610 may add reconstructed residual data to a predictive video block and generate reconstructed video data. A predictive video block may be determined according to a predictive video technique (i.e., intra prediction and inter frame prediction). Intra prediction processing unit 606 may be configured to receive intra prediction syntax elements and retrieve a predictive video block from reference buffer 614. Reference buffer 614 may include a memory device configured to store one or more frames of video data. Intra prediction syntax elements may identify an intra prediction mode, such as the intra prediction modes described above. Inter prediction processing unit 608 may receive inter prediction syntax elements and generate motion vectors to identify a prediction block in one or more reference frames stored in reference buffer 616. Inter prediction processing unit 608 may produce motion compensated blocks, possibly performing interpolation based on interpolation filters. Identifiers for interpolation filters to be used for motion estimation with sub-pixel precision may be included in the syntax elements. Inter prediction processing unit 608 may use interpolation filters to calculate interpolated values for sub-integer pixels of a reference block. Post filter unit 614 may be configured to perform filtering on reconstructed video data. For example, post filter unit 614 may be configured to perform deblocking and/or Sample Adaptive Offset (SAO) filtering, e.g., based on parameters specified in a bitstream. Further, it should be noted that in some examples, post filter unit 614 may be configured to perform proprietary discretionary filtering (e.g., visual enhancements, such as, mosquito noise reduction). As illustrated in FIG. 6 , a reconstructed video block may be output by video decoder 600. In this manner, video decoder 600 represents an example of a device configured to parse a syntax element indicating a number of subpictures in a picture and for each of the subpictures, other than the first subpicture, parse syntax elements indicating the position of the subpicture.

In one or more examples, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media, which corresponds to a tangible medium such as data storage media, or communication media including any medium that facilitates transfer of a computer program from one place to another, e.g., according to a communication protocol. In this manner, computer-readable media generally may correspond to (1) tangible computer-readable storage media which is non-transitory or (2) a communication medium such as a signal or carrier wave. Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementation of the techniques described in this disclosure. A computer program product may include a computer-readable medium.

By way of example, and not limitation, such computer-readable storage media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. It should be understood, however, that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transitory media, but are instead directed to non-transitory, tangible storage media. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor,” as used herein may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein. In addition, in some aspects, the functionality described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or incorporated in a combined codec. Also, the techniques could be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC) or a set of ICs (e.g., a chip set). Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, various units may be combined in a codec hardware unit or provided by a collection of interoperative hardware units, including one or more processors as described above, in conjunction with suitable software and/or firmware.

Moreover, each functional block or various features of the base station device and the terminal device used in each of the aforementioned embodiments may be implemented or executed by a circuitry, which is typically an integrated circuit or a plurality of integrated circuits. The circuitry designed to execute the functions described in the present specification may comprise a general-purpose processor, a digital signal processor (DSP), an application specific or general application integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic, or a discrete hardware component, or a combination thereof. The general-purpose processor may be a microprocessor, or alternatively, the processor may be a conventional processor, a controller, a microcontroller or a state machine. The general-purpose processor or each circuit described above may be configured by a digital circuit or may be configured by an analogue circuit. Further, when a technology of making into an integrated circuit superseding integrated circuits at the present time appears due to advancement of a semiconductor technology, the integrated circuit by this technology is also able to be used.

Various examples have been described. These and other examples are within the scope of the following claims.

SUMMARY

In one example, a method of signaling picture information, the method comprising: signaling a syntax element indicating a number of subpictures in a picture; and for each of the subpictures, other than the first subpicture, signaling syntax elements indicating the position of the subpicture.

In one example, a method of decoding picture information for decoding video data, the method comprising: parsing a syntax element indicating a number of subpictures in a picture; and for each of the subpictures, other than the first subpicture, parsing syntax elements indicating the position of the subpicture.

In one example, the method, wherein the first subpicture corresponds to a subpicture located at the top left of the picture.

In one example, a device comprising one or more processors configured to perform any and all combinations of the steps.

In one example, the device, wherein the device includes a video encoder.

In one example, the device, wherein the device includes a video decoder.

In one example, a system comprising: the device includes a video encoder; and the device includes a video decoder.

In one example, an apparatus comprising means for performing any and all combinations of the steps.

In one example, a non-transitory computer-readable storage medium comprising instructions stored thereon that, when executed, cause one or more processors of a device to perform any and all combinations of the steps.

In one example, a method of decoding video data, the method comprising: parsing a first syntax element indicating a number of subpictures in a picture; for each of subpictures which are other than a first subpicture, parsing second syntax elements indicating a position of the each of subpictures; inferring a top-left position of the first subpicture equal to a top-left position of the picture.

In one example, the method further comprising, for each of subpictures which are other than a last subpicture, parsing third syntax elements indicating a size of the each of subpictures, and inferring a size of the last subpictures.

CROSS REFERENCE

This Nonprovisional application claims priority under 35 U.S.C. § 119 on provisional Application No. 62/955,291 on Dec. 30, 2019, the entire contents of which are hereby incorporated by reference. 

1. A method of decoding video data, the method comprising: parsing a first syntax element indicating a number of subpictures in a picture; for each of subpictures which are other than a first subpicture, parsing second syntax elements indicating a position of the each of subpictures; inferring a top-left position of the first subpicture equal to a top-left position of the picture; for each of subpictures which are other than a last subpicture, parsing a third syntax element indicating a width of the each of subpictures and parsing a fourth syntax element indicating a height of the each of subpictures; and inferring a size of the last subpicture, wherein, parsing the third syntax element includes determining a length in bits of the third syntax element according to following Ceil(Log2((maximum picture width in luma samples+coding tree block width in luma samples−1)/coding tree block width in luma samples)), and parsing the fourth syntax element includes determining a length in bits of the fourth syntax element according to following Ceil(Log2((maximum picture height in luma samples+coding tree block height in luma samples−1)/coding tree block height in luma samples)).
 2. (canceled)
 3. A device comprising one or more processors configured to: parse a first syntax element indicating a number of subpictures in a picture; for each of subpictures which are other than a first subpicture, parse second syntax elements indicating a position of the each of subpictures; infer a top-left position of the first subpicture equal to a top-left position of the picture; for each of subpictures which are other than a last subpicture, parse a third syntax element indicating a width of the each of subpictures and parse a fourth syntax element indicating a height of the each of subpictures; and infer a size of the last subpicture, wherein, a length in bits of the third syntax element is determined according to following Ceil(Log2((maximum picture width in luma samples+coding tree block width in luma samples−1)/coding tree block width in luma samples)), and a length in bits of the fourth syntax element is determined according to following Ceil(Log2((maximum picture height in luma samples+coding tree block height in luma samples−1)/coding tree block height in luma samples)).
 4. The device of claim 3, wherein the device is a video decoder. 